Finally found a reasonably up to date SIP client/VOIP softphone that will work directly under Ubuntu 9.04 on the EeePC:

Twinkle! 

Tried many, many alternatives without success (most commercial clients that are otherwise available for Windows or Mac have not been updated for Linux for years, and the GPL/open ones are not so much better).  This one pretty much worked straight out of the “apt-get”/Synaptic box for me.  A little playing with settings to figure out the right places to put in my Galaxyvoice account info and I was off.  Phew, another task checked off.

BTW, I really like Galaxyvoice.  They’ve provided my home phone service for several years now.  Much better call quality than Vonage in my experience.  Billing is weird — the on-line account records never match what my CC gets charged… but since it is never more than $10 in a given month at my usage level, I don’t care.  Sometimes it is as low as $2!  Really, $2 to make and receive phone calls for a month – and they have a profitable ongoing business. And real people in Massachusetts take my calls for service.  You have an alternative…