Go with buses as the plural of bus. Use busses when making a plural noun or third-person present tense verb of buss, meaning kiss.
It's a bit confusing. The dictionary allows busses as a plural for the motor coach. But Associated Press style, backed by Bryan A. Garner (cue angelic chorus) and others, calls for buses. It isn't a U.S./British thing either. Fowler's Modern English Usage goes with buses.
Since most of those paid to know better are bound by AP style, there's no reason to see hundreds of articles on Google News referring to busses.
While we're at it, Garner's Modern American Usage goes with pluses over plusses. There appears to be some confusion over this point on Google News. AP follows Webster's New World Dictionary, which allows both but prefers pluses.
For those too young to remember his glory days and those who fondly recall his exploits, here's video of Evel Knievel and buses: