Currently MobileMe subscribers dish out $99 per year for what can be basically broken down to a Dropbox account and the ability to remote wipe your iPhone/iPad, so having it go free will be a big deal for folks who either said $99 per year is steep or couldn't justify the cost by not having an iPhone to remote wipe. It will be interesting to see if/how Apple will sweeten the pot for folks who've been paying the $99.
Also, lost (buried) in the original article, is mention of Apple's streaming music service which may or may not be ready in time for the MobileMe announcement. Gotta love those anonymous sources.
WSJ Online via TUAW