I wasn't having much luck finding a NEMA 10-30 to 6-15 adaptor. The main difference seems to be that 6-15 has 2 hot pins and one ground pin, while 10-30 has 2 hot pins and one neutral pin. Both are three pin connectors, not four like are common now.

I'll check with a local hardware/electrical store to see what they can do. With the apartment I'm in, I'm hesitant to modify the actual wall socket, especially with the lack of a grounding pin in the current one.