This is still the case, although all my contacts at Intel deny number 1.
Hm... Here's what I found: http://zdnet.com.com/2100-1103-993896.html
2. Presently, the Pentium M processor and Intel 855 chipsets are supported under Linux, but "Centrino Mobile Technology" and the wireless card aren't.
If by 'Centrino Mobile Technology', you mean any SpeedStep-like functionality, correct, that is the case.
Not sure. That's directly off Intel's web site: http://www.intel.com/support/notebook/centrino/os.htm