Microsoft Paint has been enhanced by many folds in Windows 7. Windows 7 paint has ribbon interface, supports png transparency, support for touch screens, realistic brushes etc. Now you can get Windows 7 Paint on Windows Vista & XP with Paintribbon.
Aviassin PaintRibbon is a drawing and picture editing application for Windows which imitates the Windows 7 Paint interface, utilizing the ribbon first seen in Office 2007. Currently paintribbon can only open and save .pic (pict) image files, however additional file types will be supported in later releases of paintribbon.
Paintribbon – Windows 7 Paint for Windows Xp & Vista
.Net Framework 2.0 is required
Paintribbon is still under development and there are lots of known issues. Do check known bugs before proceeding for installing Paintribbon.