Total time required for a manuscript to be accepted? - (Feb/22/2012 )

What is the more realistic time for a paper to be accepted into a scientific journal?

This leads to my 2nd question as to how possible is it to get published (as a first author) during a PhD duration? (more possible to get multiple 1st authorships in US since PhD runs for more years in US?)

At my institution, I must be first author on at least 1 peer-reviewed paper before graduation. It is very possible to have multiple 1st authorships if you are productive and collect publishable data.