It seems like everyone is pitching in for Haiti right now, and knitters are no different. There's a feature on Ravelry now for Help for Haiti, where designers donate a portion of their pattern sales to the Haiti efforts.
Most of the designers have pledged a percentage of pattern sales until the end of the month, and a few have extended that period into February - So, it's best to act sooner rather than later.
If you've got some patterns you're going to buy anyway, there's no better time than now. You can use Ravelry search to see what patterns you have queued are also helping Haiti - Rav search
Many popular designers have marked their patterns as Help For Haiti, including Marnie McLean and Ysolda Teague. Now's a great time to purchase those patterns you've been putting off!
And if you're going to donate directly, you can have your donation counted through Yarnharlot's Knitters Without Borders program - knitters have raised nearly $1 million for Doctors Without Borders!