arrhythmia's links are really good. they give the basics. i can make a few more suggestions. i work at an art museum with glass collections, so i have to take a lot of photos of glass, one of the most difficult things there is to photograph. i've learned a few things i can share w/you:
the longer your exposure time, the more chance you have of shaking/getting out of focus. get a tripod. you should have one that can flip the camera all the way down to face the floor for overhead product shots. if you can afford it, a copy stand is a great help if you're shooting primarily overhead shots. at work i have a small one that has a base of about 18 x 18, and two swivel lamps w/the silver reflectors are attached. it's simple but does the trick. w/a tripod, you have the option of changing the direction of the camera, where you only get top-down shots from a copy stand.
lights: having lights on stands is slick, but you can easily use swivel desk lamps or those clip lamps. you can adjust where they need to be easily enough. heck, you can even hold one in your hand and aim it where you want then take the photo w/the other.
light bulbs: get daylight-adjusted bulbs. they help soooo much by taking away that yellow cast. also, if you can get compact fluorescent bulbs, do that. they fit into normal sockets and use less energy, making them last longer and operate at cooler temperatures (working w/lighting can get hot, on both you and the subject). they cost between $15-$25 each, but last much longer.
also, when using lights, you typically don't want to have any other light sources messing w/your lighting. they add color casts, glare, hot spots, and reflections. i turn off my office's overhead lights and i have the window shaded. and i *never* use the camera's flash.
light tents: as discussed in some of the other links, you want your lighting to be diffuse. that means not using the flash on your camera, not aiming lights directly on the subject w/o some sort of diffuser or reflector, etc. light tents don't have to be fancy deals. i have a pop-up one made of nylon from a company called EZcube. it's handy for those taking a lot of photos, portable, and easily modified (2 entry points for camera, velcro to stick seamless backgrounds to, can fit stands or light panels on the bottom), but it costs $55 for a 12" square cube which may be too much for some. it does come in larger sizes, too.
if you want down and dirty, take some heavy white paper (card stock), tape 2-3 end-to-end, and bend it around to form a cone. it's like making a duncecap, but you leave a small opening at the top for your camera's lens to poke through. this will diffuse your lights reasonably well, and you can adjust the diameter of the cone to block out glare and hotspots. you will have to hold the cone in one hand while you take the photo w/the other, though.
another easy light tent is a styrofoam cooler, the kind you can find at the gas station or in the fishing dept. rectangular or circular doesn't matter. all you do is cut a hole large enough for your camera's lens in the lid. you get the ease of having a solid background and the ability to photograph anywhere. you then can take the cooler outside and shoot in daylight, not having to use artificial light. you also can put a piece of crescent board or fabric on the bottom for your piece to set against.
i've heard of people using lampshades, large bowls, and there's a post on this site for someone who cleverly used a trash can. the key is that it should be white or translucent/white colored. this diffuses the light source AND reflects light back on the subject.
if you don't use a light tent, you'll need to set up pieces of foam core/white crescent board to make almost a diorama (there's a post/tutorial on this site that shows how one person does this). also, you can have someone just *hold* those pieces and reflect the light back; this way, you can adjust it the way it needs, but you need another set of hands. you can hang a white/light colored curtain in front of the light source, too (not too close!), which mimics the umbrella or "soft box" photographers use. and finally, you can cover a board w/some tinfoil for reflecting, too (photographers have fancy-schmancy ones w/metallic fabric on them).
background: all you need is a piece of crescent board for your piece to sit on if you're shooting from above. crescent board is easy to find at art supply/craft stores, and sometimes it's in the school supply section of regular retail stores. it comes in many different colors. i like having some black, white, and grey on hand, just because black objects show up better on lighter backgrounds, etc. in a pinch, i will use a piece of heavy paper (card stock). works fine.
if you use a light tent, you will need to have a seamless background. this can be heavy paper on a roll, fabric, or i've even seen people use the pull-down window shades. again, i have several colors. my light tent came w/a white seamless background that velcros in. there also are some loops where i can "hang" some other backgrounds from. i have some velvet remnants that i use, black being the most used after the white. all are solid colored, which looks better AND makes it easier to retouch or drop out in photoshop.
stands: some things need to be held up or at an angle. sometimes you have things that look nice or are unobtrusive, sometimes you will just photoshop the support out. i use acrylic risers, as that's what we have in abundance at the museum. but those aren't something you can find everywhere, so you can use whatever holds/supports your piece and looks nice, or just cover your support/stand w/fabric matching your background. for a few things, i've used those wooden plate holders and just draped them w/fabric. or i've cut-and-pasted cardboard easels and spray-mounted velvet on top.
i found a black acrylic riser which makes for some really snappy shots when used w/a black seamless background. drape the background, then set the riser on top, and your piece on the riser. you get a soft reflection in the riser, which is really classy. you do have to be careful what *else* reflects, though. you don't want people to see you, the camera, the lights, etc.
i can suggest one more tutorial that discusses optimum lighting for different materials. it's on the website where i bought the light tent. if you just ignore their plugs for the EZcube tent, it actually has some GREAT info on there, esp for difficult materials like glass:http://www.ezcube.com/documents/whats_so_great_about_an_ezcube.htm
i think i hit most of the big points ...