The Mars Phoenix Lander will be touching down on the surface of Mars on Sunday at 23:53:52 Universal Time (4:53 p.m. Pacific time). Of course, there will be lots of action leading up to that moment.
You can get live info from a few different sources.
For online video and such, your best bet is NASA TV. If you have it, The Science Channel is covering it live on TV. And if you want live blogging action, Emily's your destination. She has a nice schedule on her blog of the whole thing. She's also been doing some great blogging on the pre-landing press conferences, so she has all the info you want. And if you're in the Tucson area, the Lunar and Planetary Institute Lab has a ton of stuff going on for the whole family.
As for me, I was thinking about Twittering it, but now I've decided I want to sit back and enjoy it, and let others worry about conveying information. I'm not an expert on Mars or Phoenix, so for once I'll be a consumer.