I loaded WM6VOIP and the config tool, but I can't find the client on the phone to launch it. Any advice?
I was never able to find SIP client for Windows Mobile that works perfectly. Even built-in (now abandoned by MS) voip library that is supposed to integrate well with phone interface sucks big time and often doesn't work as expected.
On my iQ I've tried
portsip and it works, it is a bit ugly and doesn't handle well screen rotation but does the job if you need to place a voip call over wifi or 3g. Best of all - it supports G729a which works out quite nice over 3g.
As for the vm6voip - check under settings/personal/phone - there should be "Internet calling" tab now. It won't work with LG idles interface or the Titanium today screen. It has plugin only for windows mobile classic today screen (you can enable it under settings/today on items tab. Make sure Internet calling is enabled under phone settings. Beside sipconfig you need to build proper dial plan for voip client to be able to work properly (it integrates with built-in dialer). That's a bit tricky and very much depends on where you are and what SIP provider you use. Default dialplan (depends on where you got your VM6VOIP library) will likely not work.
Portsip is much less of a trouble to use as it has its own dialer and relays on the SIP provider for dial rules.