I'm glad to know this is coming. I moved my other cloud stuff to iDisk last night and deleted those pieces from my MacBook and iPod touch, so now things shuld all be in one place this time next week!
EDIT: I wonder if this will enable us to save attachments from Mail and files from Safari now, also. It seems like the problem earlier might have just been nowhere to put the files, but with an iDisk app we could save directly to that, have it uploaded to iDisk, and we're set.
This doesn't make much sense for Mail, but I can think for small files on the Net this might be ideal.
Is this completely unreasonable to assume?