SoonR allows you to connect to your computer (PC or Mac) and look at files, emails, and appointments via a cell phone that can connect to the web. Today SoonR has released a beta of their client for OS X. The coolest thing about this client, in my opinion, is that you can do a Spotlight search on your Mac at home via your cell phone.
I'm not sure how useful this will be, but it is very cool. Basic Soonr accounts are free, though upgrading to a premium account will cost ya (a premium account includes backups, access to host computers even when they are off, and cheap international calling).