Here is a little class that lets you present percent complete information in the form of a progress bar using the '#' character to represent completed portions, space to represent incomplete portions, and the actual percent done (rounded to integer) displayed in the middle:
[############# 33% ]
When you initialize the class, you specify the minimum number (usually 0), the maximum number (your file size, for example), and the number of characters wide you would like the progress bar to be. Note that width includes the brackets  on the ends of the progress bar as well.
You'd probably want to use this in conjuction with the curses module, or something like that so you can over-write the same portion of the screen to make your updates 'animated'.
def __init__(self, minValue = 0, maxValue = 10, totalWidth=12):
self.progBar = "" # This holds the progress bar string
self.min = minValue
self.max = maxValue
self.span = maxValue - minValue
self.width = totalWidth
self.amount = 0 # When amount == max, we are 100% done
self.updateAmount(0) # Build progress bar string
def updateAmount(self, newAmount = 0):
if newAmount < self.min: newAmount = self.min
if newAmount > self.max: newAmount = self.max
self.amount = newAmount
# Figure out the new percent done, round to an integer
diffFromMin = float(self.amount - self.min)
percentDone = (diffFromMin / float(self.span)) * 100.0
percentDone = round(percentDone)
percentDone = int(percentDone)
# Figure out how many hash bars the percentage should be
allFull = self.width - 2
numHashes = (percentDone / 100.0) * allFull
numHashes = int(round(numHashes))
# build a progress bar with hashes and spaces
self.progBar = "[" + '#'*numHashes + ' '*(allFull-numHashes) + "]"
# figure out where to put the percentage, roughly centered
percentPlace = (len(self.progBar) / 2) - len(str(percentDone))
percentString = str(percentDone) + "%"
# slice the percentage into the bar
self.progBar = self.progBar[0:percentPlace] + percentString +