A lot of us are probably using the Screen Capture function on QuickLaunch, but probably equally many people use CaptureIt, a dedicated screen capture app.
Another one to try is ZonaSnap... I've had better luck with that than Capture It and you can use it to easily post from WAP if you don't feel like logging into CB from your computer. Anyway, after you take the shot of your screen with the application of your choice, just upload it to Photobucket or another similar image hosting site, post the direct link here, and wah-lah.