I signed up for Twitter this weekend. Its pretty cool so far. Just IM an address (gmail/aol, etc), send a txt, or update from the web. You can update people on what you are doing. Also, you can get alerts when people update what they are doing. I also put a badge on my blog on the right. Pretty cool app, form the same guys who made Odeo
BTW, my Twitter username is ScaleOvenStove