In case anyone was wondering I was just over at Itourtree blog, and the GEDCOM import allows you to zip your tree.  I don't know how big, is the target to try and zip your tree, but they state if you are having time out issue's to try and zip your GEDCOM, the servers will automatically unzip it for you.
I dont know if any of the other online sites allow this, but I think its pretty neat, and will probally help in the long run.