Now, We know Echolink will not run on Windows Mobile but don't give up hope. I have a HTC Touch Pro 2 and I run WM 6.5 but I'm now using less and less. The fine folks over at XDA-Developers have come up with the XDANDROID project. This is Android for some of the older smart phones, Not that mines not that old. The system is loaded on your SD card and boots from your SD card. The first App I downloaded from the Android Market was Echolink and it works very well.
Go the the XDA forums and scroll down to your phone and start reading. There are some things that have bugs still, like key board led and Bluetooth. You will have to see what is working and not for your make of phone. They do update often so you will have have to keep up with updates.
One other web site to check out is PPC-Geeks. So get Android download the Echolink App and get on the air!