This can't be good...

[JustinMorrison]

Yesterday when I arrived home from a friends house I noticed that there was smoke coming from the beneath my car (1987 560SEL). I popped the hood and everything looked fine, no smoke, no nothing. It was a hot day (for Northern California, maybe 80 or so), and I had the AC running. The engine temp guage wasn't excessively high, oil pressure was just under 2...basically everything (except for the smoke coming from under my car) was normal. I got down and looked for the source and it looked like it was coming off of the exaust pipes (not out of them, more like if you poured water on hot metal and steam came off the metal). So, what's the deal? Can I safely drive to my shop or should I have the car towed? Thanks in advance for any help!
Justin