One of your options when you have film developed at a retail mini-lab is to have it scanned and burned to a CD. This is undeniably convenient, especially if you don't have a scanner of your own. The quality of the scans is often better than you might think, but a lot depends on who's doing them.
How can you tell if a scan is of reasonably good quality? Aside from the quality of any accompanying prints, take a close look at the scans on your monitor to make sure there are no film scratches, dust, or excessive grain. If you've got an image browser or pixel editing program with a histogram feature, use it to see whether there's clipping in the highlights or shadows.
In general, the less tweaking you have to do, the better the scan. This is important because mini-lab scans are almost always in JPEG format, so any edits and re-saves you do will erode the image data.
In case you're wondering just how good a mini-lab scan can be, here are two samples. One was done was done at a local camera shop, the other on my Nikon Coolscan V film scanner. Can you tell which is which?