The folks at Twisting Pixels have some really cool plug-ins that work with Adobe Photoshop and Corel PHOTO-PAINT. Recently they added a new plug-in that can make your photos look like a painting by one of the masters.
ArtStudioPro Classico gives you filters like Aged Paint, Artistic Edges, Cracked Paint, DaVinci, Graphite Sketch, Sketch, Painted Background and Vintage Sketch. With each filter, there are a number of settings you can adjust to get the exact look you want.
You can download a free trial version of this and other Twisting Pixels plug-ins as well as purchasing full versions at the Twisting Pixels Web site.