In case you haven't seen this, it's an awesome add-in project that you'll want to try out. I found it via the vs2005news's WebLog. This add-in creates a zoom control toolbar that lets you specify the how much you want to magnify the text in Visual Studio. There's a project for Visual Studio 2003 and one for the 2005 December CTP in the project workspace. Check it out here:
VS Editor Zoom: Workspace Home
Just like Words zoom control, adjusting the value of this control will increase or decrease the font size in the Visual Studio Editor.
To use this add-in, you'll need to build it. If you're not interested in debugging the project, I would unzip the project, then rebuild all. In the Solution Explorer window, right click on the setup project (ZoomAddinSetup) and click Rebuild. You'll find Debug and Release folders in the ZoomAddinSetup folder. Close Visual Studio and run the Setup.exe file in the Release folder. When you open Visual Studio again, look for a little toolbar that contains the control. Drag that onto your toolbar area for easy access.

This looks like an especially cool add-in for people doing demos. You can work with a normal font and then you can zoom in on just the code you want the audience to see. Very nice. Get more information at the IDE team's Powertoys Page on GDN.