Linus Torvalds is at least a multi-millionaire; when RedHat and VA Linux went public, they each gifted him with shares in gratitude for inventing Linux, reportedly worth around $20M [1]. Some sources put his wealth at anywhere from $150M [2] to $1B [3]; his actual wealth would vary significantly based on when he sold and what he's invested in since, since those shares shot up 10x on IPO day.
hm ok, i read some article on that suggesting that he didnt make much money at all from the RedHat stint. But yeah i am sure he is a millionaire, but i am also sure Guido is too, just considering what he earned at Google for the last 7 years.
[1] http://en.wikipedia.org/wiki/Linus_Torvalds#Later_years
[2] http://hollywoodnose.com/net-worth/linus-torvalds-wealth
[3] http://money.cnn.com/magazines/fortune/fortune_archive/2000/...