Woah. I must have been sleeping in a cave somewhere. Thanks to Ars Technica, I was pointed to an Apple page describing 250MB combined iDisk and .Mac Mail storage. It's not a flat-out gig, like GMail, but it's a heckuvalot better than the 15MB for mail, and 100MB for iDisk...
I just poked around on .Mac, and it's official. Cool! You have to dig into your account settings to tweak how you want the 250MB used (by default it uses 125MB for mail, 125MB for iDisk). I have my .Mac account forwarded to my GMail account, so I set my iDisk to take the lion's share of my space.
UPDATE: OK. So, I wasn't sleeping in a cave or anything - this was just announced. It's not a gig, but it's sure better than having what amounted to an online Zip disk...