As far as I know, you can mount the .sparseimage, and run "Repair/Verify" in Disk Utility, like you could on any other disk....
And like any other disk, always try to "eject" or dismount before powering off or restarting the computer..
I have seen them get corrupted before, but not for a long time... I think it might have been a non-Snow Leopard issue. BTW, sparse "disks" are how Apple stores your "Home" folder when you use FileVault (which are gone in Lion, so don't go ecrypting your home folder, now... they just encrypt the whole disk)
My favorite command is the following, which shrinks the sparseimage down to the actual amount of data you have stored in it, no matter how large it had grown to by adding files which you have now deleted..
hdiutil compact /Macintosh\ HD/Path/to/Name\ of\ file.sparseimage
BTW, the backslashes ( \ ) are only required if you have spaces in your file pathname.