A poor, direct to video effort in every department, this manged to secure Samuel L. Jackson and garnered quite a following on the internet due to it's crowd pleasingly stupid title.
B movies live and breathe largely depending on two things: a genuine wit and invention (Tremors for example) or a fast enough pace so you don't have time to think about how daft it all is (say the transporter) or preferably both (e.g. the highly enjoyable time travel romp Retroactive).
Snakes on a plane has neither. It takes twenty minutes before the plane even takes off and another excrutiating ten minutes before there's any damn snakes.
And when they do finally get the meat of the film it's an incoherent mess of dull, badly acted characters and absolutely no tension at all.