I came across this free software, Teamviewer, months ago. My friend Sundar (www.sundareswaran.com) introduced it to me.
Teamviewer lets you control and transfer files to someone else's computer. I find it very useful for team collaboration (It would be like sitting next to your partner at his computer). Plus, it has a chatbox, where you can chat with your partner on Teamviewer.
For example, Gaya wants to help Farrhad to redesign WMP. So, Farrhad and Gaya goes on Teamviewer. Gaya controls Farrhad's computer and edits the CSS code (But once Farrhad takes control, Gaya can't control his computer anymore).
But at one point, Farrhad disagrees with Gaya on the color. So, he opens the chatbox and discussed about it with Farrhad. Finally, Gaya agrees with Farrhad's choice. They then continue to redesign WMP together.
I also find it useful when you don't know something, and need help.
For example, Nic doesn't know how to change the structure of permalinks in his blog to make it SEO-friendly. So, he asks Simon for help.
Simon then navigates through the admin area of Nic's blog through Teamviewer and teaches him how to change the permalink structure.
To get control of your partner's computer, he needs to give you his Teamviewer ID and password (By Instant Messengers or something).
Teamviewer can be downloaded at www.teamviewer.com for free. If you have used Teamviewer before, please tell about your experience with it on this thread.