Perhaps people could give you the answers you're looking for if your question was better than "huh"?

802.11a is the same in speed as 802.11g, but it runs at 5.8GHz instead of the cluttered 2.4GHz radio frequency band.

'a' might have a slightly shorter range than 'g' simply due to the higher frequency (higher frequencies have less penetrating power through walls and such) but otherwise you can expect the same performance as 'g' and less interference issues.

'a' is definately the way to go - especially since many vendors such as 3com offer corporate access points that support a/b/g simultaneously.