Windows Mobile networking profile switching
The problem is that when you are somewhere that requires you to specify your WiFi connection's IP address, you need t change your settings from using DHCP. And you get sick of changing it manually! Like Dave Gardiner says, it would be useful to have a network profile switcher.
A friend at work recommends http://www.hudsonmobile.com/products/ipdash/index.html. Says it's very good - and it certainly looks it.
Another option would be to roll your own. The registry contains the details. I use TRE registry editor, which tells me that HKLM\Comm\tiacxwln1\Parms\TCPIP contains the useful stuff for this. So it should be easy to write an app which alters the entries there, and prompts you to save the settings as a profile you could switch to later.
Of course, writing one isn't my highest priority right now, but I'll try to do it some time...