From what I know, very few virtual machines have good support for Windows 98se. The best I've tried are Vmware player, and Virtual PC 2007. You could try installing Windows 98se in a special build of DOSBox that supports Glide emulation. It can be a complicated process, but just might be a solution to your problem.
Another solution is to search the Internet for fan-sites and communities for the particular game you are trying to play. Sometimes they release patches and software that can help you get the games running on a modern PC.
If all else fails, you could try building or buying an older PC to specifically play those games. On several websites, I have read about people who think this is the best solution to playing old PC games (although I've never really tried it myself).
Link to DOSBox with Glide support
http://ykhwong.x-y.net/
Link to guide on how to install Windows 98se in DOSBox
http://vogons.zetafleet.com/viewtopic.php?t=26973