http://omnisio.com/startupschool08/mike-arrington
Main point: Tell a story. Don't just bombard him with the same bland description of your site. Leak information so that he can piece together a greater conspiracy. And make the process of giving information valuable, as in not constantly talking about your startup in twitter, but just leaking little tweets here and there so as to make people think they've discovered a gem.
Watch the video. He really does describe ways to get TechCrunched.
My startup was profiled earlier this year (and it was a great generator of traffic, leads -- and customers). So, at least in our case, it was worth it.
Essentially: Make is short, not more than a couple of sentences and relate it to something already existing.
Look Here: http://tinyurl.com/5lacfh
If you're 'new and growing' that won't work, so keep in mind there's more to TechCrunch than Arrington - I met Duncan Riley at BlogOz last year, and if he's a reflection of the other bloggers then they're all approachable and keen to hear your interesting story.