Yes, if the firm-ware has been updated then you can connect a external hard-dive and ahare it on a network.
If use a hub you can add printers too.
You can even archive your time capsule onto a USB drive. (there was a problem at the begining of the year doing this with some firm-ware versions in that trhe back-up disk images appeared as folders rather than bundled files. This I beleive has been fixed)