Your question is very vague, if you want to give some more info about what you have and what you want to do, someone can point you in the right direction (how many pc's, where is your data, how much data do you have, will you be using the same laptop or workstation to access it remotely, what is your internet connection, etc?)
Here a few generic solutions: buy hosted disk space, using a program to remote access your pc, vpn to your home network and access a pc there.
There is Go Dadddy's "online file folder" that can give you a one gig harddrive in their data center for 10$ a YEAR, different plans available. www.godaddy.com look under Hosting.
If you want to access your home pc via broadband, check out www.gotomypc.com there is a trial if you want to check it out. To bad it's 20$ a MONTH
If you want to VPN, again assuming your data will reside in one location with a high speed internet connection, I suggest you get a Cisco PIX 501 and use the Cisco VPN client on your roaming device. This will not help you if you want to use public terminals since they won't have the software on them. Plan 500$ hardware and 500$ for someone to set it up and load your client on your pc. You may have problems getting a static IP from your ISP, could cause problems.
There are other VPN options available, this is just the one that I usually build, most will require either a special piece of hardware, or a dedicated server.
FTP is usefull when many people need access to a set of files from different places, and some people need write access, some read only, etc. Think about linux distro's, good solution for FTP.