As of 02-16 03:07 PM, 5 Whenever minutes used. Bill Close: 02/24(and, for the record, I've used 68 of my ∞ weekend minutes)
It looks like TMTG does have some sort of GPRS access now, but it's very limited and I doubt it supports email and Google Maps (which are the only things I use GPRS for). I think Cingular does have a pay-by-the-kilobyte option for their pay-as-you-go, but their minutes expire so quickly and are so overpriced, and their site is so freaking confusing... (although the cost per minute would still be way less than what I'm paying on T-Mobile monthly).
Even in January (which was a relatively heavy month for me) I only used 60 minutes and 64 text messages. That would have been $12.40 on T-Mobile To Go (half of that from the text messages!).