I have had a Treo 650 for a few months. I got it on eBay. Several of my colleagues have Treos and they've all had some difficulty getting it to do email and browse the Web. Each cell carrier wanted them to do something a little bit different. My carrier, T-Mobile, had a fantastic bargain for Internet connectivity through their WAP proxy server, but they would prefer that customers use their more expensive (and more flexible) Internet service. I had to rely on blogs and forums to configure the proxy server, but once I did, I've been very happy. I can use the built-in email program and the built-in Web Browser as much as I want for very little dough.
My next project was to get the bitty screen to be a hand-held marine GPS system. More uncharted waters for me. First, I bought a very small blue tooth GPS receiver from eBay, but I couldn't get it to sync with the Treo. I talked the eBay seller to sell me a different model--not as small with batteries that don't last quite as long. After a couple days of fiddling, I got this model to sync with my Treo. Afterward, it occurred to me that the first GPS receiver may have worked too if I had known what to do.
Now, I needed marine navigation software for the Treo. This turned out to be much more difficult that I thought it would be. I thought I could use something like Tom-Tom, which makes nice automobile navigation software for the Treo. The fact was, I had only two choices and I chose the cheaper path. However, the cheaper path required that I learn to navigate the Windows-centric world more than I wanted to. With the help of a forum member, I was able to get some Mac OS X software that got me over the top.
Next, Installing Pathaway marine navigation software on a Treo and loading maps from OS X.