This is a 25-page white paper on cloud computing from Sun Microsystems. For those who know nothing about cloud computing, this will be a good starting point.

Many commercial cloud computing services are now available, including those from Rackspace and Amazon (very famous). Cloud computing services are like server hosting services, but they give you huge power on tap, for a few hours, billing your credit card. So if you need one server for six months, you can get it from a hosting service provider, but if you need the power of 20 servers for one weekend, you can get it from someone like Amazon, with a delay of perhaps 10 minutes.

Sun apparently plans to offer a cloud platform too.