What version of Windows do you run?
Here's what I do on 98 SE:
1. Hit the "Print Screen" button. On a standard keyboard it's between F12 and "Scroll Lock", just above "Insert"
2. Alt-TAB to switch programs
3. Open Paint (found in Start Menu/Programs/Accessories)
4. Use the "Paste" command, and my screenshot appears. Paint always asks if I want to resize the bitmap--I say yes.
5. Save the screenshot as a bitmap (that's the only format Paint uses.)
6. Alt-TAB again, select T2, and continue playing.
7. If I want to post a screenshot, I use a photo editor to convert it to JPEG.
This should also work in ME and XP, unless the game reacts unpredictably to Alt-TAB when running on those OSs. Some games aren't happy if you do this, but Tropico and T2 both seem to handle it well.
Let me know if this works. I know Severous did a good explanation on this question, but it's faster for me to type something out than find the thread