You might check out the latest version of Roxio Toast or Popcorn. If it works at all, though, the conversion process will be very CPU intensive and the image quality will suffer from the re-compression.
Best results will come from getting a multi-format DVD player and watching them on that. It'll be cheaper than buying Toast 8 at the MSRP.
has lots of info on players, including which ones can be converted to region free, so you can play DVDs that you buy abroad.
Depending on the copy protection on the VCD/SVCD, you might even be able to plug the player into your DVD recorder and do a direct copy.