You can set up a Time Capsule for remote access from the WAN/web (one of the options in the airport utility). Seems to work fine for Macs but PC file sharing is usually blocked by ISPs so you shouldn't expect it to work. There are several on line guides. If your ISP is not blocking windose file sharing, then it should work fine for PCs too. Make sure you use a strong password, a more secure method would be via a VPN.