The conversion was done in moments. Next, I navigated via my iphone 3G to http://www.google.com/voice/m and logged in there. The new google voice works wonderfully well on the iphone, messages play as quicktime movies. I've been using Grand Central for over a year, and recommend it highly.
I checked over my settings, and noticed that my customized call groupings had been hosed. Not a big deal to straighten out. Basically, in the conversion the process assumes all caller groups should ring all phones and that isn't how I had it set up before. And the caller groups are missing anyway, so I'll have to recreate those. Also, I will need to record new greetings; my account was reset to standard greetings.
Later today, I'll try digging into the SMS, voicemail transcript and conference call features. And check it out - Google spiffed me a dollar for being part of the beta. Thanks, Google.
More updates have been available via twitter at @GoogleVoice.