I just got the nicest surprise on my iPhone. I don't know how long this has been going on, but my AT&T Pay as You Go feature packs just got much, much better. If you're a PayGo customer for an old iPhone like I am (I use PayGo with my 3GS), your $5 now buys you 50MB.
Here's a quick comparison of the old and new allocation amounts.
Feature Pack Cost
Old Allocation
New Allocation
$5
10 MB
50 MB
$15
