Honestly, that seems a little weird to me. It's like saying "I'll make the 'sacrifice' of doing my hobby for 8 hours, and by the way, I get the tax break on the donation because you'll be sending the cash to me." If you're going to do something virtual, I think your friends and families would probably find it more fun to donate if you pledged hours at a food bank or something.

I think it would be better to do something where people get to participate, like having the people you would expect to donate come over to your house for a board/card game night, sort of like charity poker, except everyone is playing for the same charity (or, everyone could pick a different charity that is working with Haiti right now). Maybe get some simple little prizes (even funny little certificates would be cool), and put out some snacks and drinks. Before people come over, they could each try to get their coworkers/friends to fill a jar with change, and the person whose change jar is worth the most gets a silly prize. At the end of the night, everyone can tally up what they won for their cause, then donate it online. That way, everyone gets to make their donation, get the tax credit if they want it, and have fun cheering each other on. Even if the night had a $10 buy-in, with 15 people playing, that's $150.

Post of Facebook/Twitter/whatever about your event, and ask that if people cannot attend, they donate straight to the Red Cross or other reputable charity.

If you are going to do something virtual, have them donate straight to the charity themselves. Just send a "bill" of how much they owe the charity. I think that avoids all problems.