If you were to log in, you'd be able to get more information on your fellow community member.
I'm an expat who has been living in Puerto Rico for about 2½ years. A lot of what you have said is accurate, but I wanted to fill in some details.
1) Cellular service
Your phone should work here. The local cellular companies are Cingular, Verizon, Sprint, Centennial, SunCom (formerly AT&T) and MoviStar. My brother has been able to use his TMobile phone here in roaming mode. I'm not sure about NexTel, though. Sprint and Verizon also offer mobile data plans, with pricing comparable to those in the mainland.
2) Internet service
There are more wireless hotspots being offered now. San Patricio Mall in Guaynabo has free wifi, as do some Chili's restaurants. Broadband access is about as widespread as you'll find in the mainland. I live way out in the suburbs of San Juan, and I was able to choose between the phone company's DSL and the local cable outfit's offerings. There are several companies that get set you up with faster connections as well.