Just seeing fan speed is seldom the objective. I want adaptive cooling, speed control of the fans so as to minimize noise. What in Linux does that?
Ah... but that wasn't your question in this thread :-) You might try taking a look at http://ipmitool.sourceforge.net/ I've never tried it, but some claim it can control some fans... seems rather hit and miss... I have no experience with it though. On my laptop I can control a few things by simply echoing a new value to a parameter in /proc/devices/... like... CPU scaling on the Centrino processor. It may be possible to do the same with fan speeds - assuming that the MB supports fan scaling. You could also go for a hardware solution and install a fan controller.. you know, the ones with the speed knob on them. Or... something like this http://www.ripnet-uk.com/reviews/coolers/pyramid/page1.shtml with is kinda cool in a nerdy sort of way. Or replace your stock fans with low noise "smart" fans... Otherwise I don't have any suggestions for you. I've never seen fan controller software and Googling around didn't help much either - at least not on the search terms I used :-)