itertools.foo(*A)

gistfile1.py

from itertools import *

def matrix_range(N,M):
    return map(lambda i: range(i,i+M),range(0,N*M,M)) #Create a MxN matrix (for testing)
A=matrix_range(5,3)

At=zip(*A) #transpose
At2=map(list,zip(*A)) #transpose without the tuple problems (slower)
At3=map(list,izip(*A)) #could be faster for big lists
a=chain(*A) #flatten to vector, lazyversion: http://docs.python.org/library/itertools.html#itertools.chain.from_iterable