Why don't you all use Application Sharing?
1. Make sure that you and your partner have Windows Live Messenger beta or MSN Messenger installed.
2. Ad him/her to your contacts list.
3. Open an instant message window and from the Actions menu choose Activities. From the list of activities that appears choose Application Sharing.
Using application sharing you and your partner can do as it says: share any application. You can give hom/her control so that he/she will be able to use it remotely if desired as well.
If Application Sharing fails use Remote Assistance under the Actions menu as well. Remote Assistance allows the other person to see and if allowed interact not only with one application but with the whole desktop.
I used to do a lot of Application Sharing in the past and even used to share my browser (IE) with my friedns and browse together.