I have been using a simple file sharing service called Dropbox that has absolutely eliminated the use of my USB data stick (in terms of mobile storage). Dropbox allows you 2GB of free storage and you can sync a shared folder with home, office and laptop. In addition, the file sharing service has unveiled apps for iPad, Android and Blackberry mobile devices.
For a workaholic like myself having all my work in progress files available in the cloud is critical. The other bonus of Dropbox is how simple sharing a file or folder via a public link can be with someone. The picture to the right depicts a stock photo purchased that I sent to a graphic designer with one click. Other simple file sharing services or cloud storage include box.net, drop.io, senduit.com, and yousendit.com. All sharing services have their specific features you may find useful in your daily grind of churning out work.
My second favorite storage service would be box.net which gives you 1GB of storage and has a 25MB file size limit. Although, it is important to mention if safety and security is a concern, then senduit may be the free file-sharing service of choice for files that need to have a time limit for expiration. It can be downloaded by your customer, vendor, partner for a limited time only then expires.
Enjoy, and happy file sharing!