Use GameCam. I used it in this video:
http://media.putfile.com/PuP-With-Power
You can get it for free at
http://www.planetgamecam.com/
The only problem some people have with it is its a bit more advanced than most people like. (You actually have to profile something.
Just expect 10-20 minutes configuring it.
Here I'll try to make this easy.
Open it up, an icon will pop up at the bottom right.
Right click on the icon.
Click Profiles
Click New
Click browse, find your guild wars shortcut or the guildwars.exe file, and click open.
Then for the profile name type in Guild Wars.
Target path should already be filled out.
For target param, type in +game dcmod
Now at the bottom right of that window press close.
Close Guild Wars if it is open.
Right click the Game Cam icon again, then click profiles, then click the Guild Wars icon, and Guild Wars will open.
Press the / key to get the game cam mouse, and move it to the top left to get to the 'remote' and you can press record, stop, sound on/off or whatever. Once you play around with it (after right clicking on the icon and exploring the menus), you will find the list of hotkeys, and you can modify them yourself so you don't even have to bother with the remote anymore!
Enjoy!
If you need any more help gamecam has a help section on their website.