VCDs are a lot like DVDs in format, but usually lower resolution (and recorded on CD media instead of DVD media, of course). Depending on the resolution, converting will likely cause a resampling of the video, which may or may not give great results. Given that most newer DVD players and all computers with CD drives and the correct software will play them, are you sure you need to convert them? Given the whole DVD+R vs. DVD-R, I've actually had slightly better luck with VCDs and playability than DVDs.
If you do, you may be able to just copy the .DAT files off the VCD (in the MPEGAV directory), rename them to .MPG, then create a DVD with those using Nero or whatever DVD creation software you have.