This post is a good primer on PR basics. If you'd like to read more on the subject, I (also) wrote a book about startup PR with plenty of examples (and a few jokes).

The Burned-Out Blogger's Guide to PR: http://www.amazon.com/The-Burned-Out-Bloggers-Guide-PR-ebook...

(I used to write for TechCrunch and have subsequently done PR consulting for startups. Feedback on the book has been quite positive; if you read it and wish it covered something, let me know!)

tips at techcrunch.com is your best bet, everyone at the company is at the end of that email. do a short email with a story hook in it.

Jason Kincaid's book is really really good:

http://www.amazon.com/The-Burned-Out-Bloggers-Guide-PR-ebook...