Visual Voicemail from T-Mobile, upon invocation, directs me to http://m.web2go.com/dsb/vvmupsell. Nice try for the application that is supposed to be seamless - and that is right after the call to T-Mobile to make sure that no changes to my account are necessary (some concerns expressed here) and no further actions are necessary.
UDPATE: Version 1.0.5 clearly states: You do not have access to Visual Voicemail. Please upgrade your account. Upgrade? To what? I thought I had all the bells and whistles already?
Calling T-Mobile, again.
UPDATE 2: Rep said something about "legacy G1 plan", then sent me to G1 department that replaced my existing plan with "G1 data plan with visual voicemail" (explicitly stating that there is no price change, just the "new plan code for internal systems"). Promised activation time of about 2 hours, but SMS confirmation came in less than 5 minutes, and it works now.