Go here http://www.merriam-webster.com/dictionary/mobile click on the noun and you can hear the pronunciation
mo-beal. rhymes with automobile. you don't say "automobull." same root word/idea.
but it may be a regional thing. i hear it both ways here in SoCal.
BrookeNicole09:I say like mo-bul/ mo-bil
Me too. Like a Mobil gas station.