I personally find two software very useful in this situation: Dropbox and Collabtive.
Dropbox (i'm sure FS devs are fed up with it currently) is an amazing peace of software, that appears in a form of folder on your desktop. This folder is constantly synching everything you put in it on an online server, and everything put in a subfolder named "public" has a public link! so no more opennig webpages to upload files or images, just save them in the right location. And the most useful feature is setting up a shared folder with other dropbox users. For example, you have a team of artists, designers, coders etc... You have a shared folder between you, and every peace of art that the artists saves in it appears on all the team members' pcs! A huge time saver. If you need more info, i could post some screens and a tutorial on how to use it.
Collabtive is a web script for collaborative project management. It features milestone tracking, multi user on a project, file upload etc... all in a very nice interface. It's hard to describe, so i suggest you give it a test run and judge it by yourself:
a screenie:
The demo link: http://www.opensourcecms.com/groupware/ ... admin.html
Admin Username: admin
Admin Password: demo123
What tools do you use to improve team collaboration?