It worked for me and most of the March 2010 moms in the thread I'm in! I've actually heard of it working more often than not. Of course, it's not something you should take and then go out shopping because it says you're having a boy or a girl, but it's fun and usually 80% accurate if you follow the instructions properly.
It's also only 30 bucks. You can get it on their website or off ebay with free shipping.
I bought one but I can't take it until week 10. I'll let ya know. I am not buying anything gender specific, even after my ultrasound. I had a friend who had to return everything. I thought I wanted it to be a surprise, but I think I would like to know what they "think". I won't be having a pink or blue shower tho.