1. Open your favorites folder (Start - Favorites - [Right Click] - [Open]
2. Create a new folder called "Window Size".
3. Copy any internet shortcut you already have in your library and paste it into the Window Size folder you just created.
4. Rename the Internet Shortcut you just copied to "640X480".
5. Right click on the shortcut and choose "Properties" from the menu.
8. Repeat for the other two shortcuts. (And add any other resolutions you'd like.)
9. Please note that the given resolutions have 20 pixels removed from their heights to account for windows users who don't auto-hide their start bars.
640 X 480
800 X 600
1024 X 768