I see a couple of options... (From the research I've been doing lately)
There is a converter that allows you to use a Dreamcast controller with a PC (I found it at
Level6.com).
With this you could use a Dreamcast Steering wheel with your PC as well...
Or you can get a couple of Playstation converters... (PS->PC & PS->DC) and use a Playstation Steering wheel.
I haven't seen ANY options to use computer controllers with console systems... PC hardware is always so different (hence all the stinking driver issues with every new piece of hardware). Honestly I don't know if you'll find anything to conect your PC wheel to the DC.
But by all means, if you do find a solution please post it here!!! (And since I hadn't specifically been digging for this idea, I'll keep my eyes open as well)
Good luck.