http://www.rafflecopter.com/ This is a website that I've seen a lot of blogs use. I didn't realize till I just looked through their site that it has a monthly cost. I'm guessing you don't want to pay to give something away.... but if you happen to be looking for a giveaway platform, this one's dead simple (at least for those signing up for the giveaway, I've never used it other than that). It let's you set social media opportunities to earn entries, such as "tweet for a chance to win" (or just give entries away). Just a good tool I've seen used.