In addition to looopy's advice...
You might want to create a few press kits but don't send them out without contacting who you are sending it to.
I work at a PR agency and our practice usually goes like this;
Develop your list - magazines, local papers, etc = whoever you are trying to reach.
Verify you have the right people (many times websites are outdated and editors/writers have already moved on)
Send out your press release to your list.
Followup (later in the day or the next day) with your core group (or all if you feel the need) of people on your list.
If you get a response back or if someone sounds interested - then offer the kit.
This way you do not spend extra time/money on creating and sending out kits on people who might not be interested at all. Verifying your contact list is also a time saver if the contact has moved on - you wont' have to waste time tracking down your kit.