Specifically for your case, help on the re.MatchObject
can be found at
http://docs.python.org/2/library/re.html#match-objects for Python 2.x or http://docs.python.org/3/library/re.html#match-objects for Python 3.x.
Additionally, as Mark writes, you can call help
on the interactive console. If you don't know how to get to the interactive console, you can just call python
or python.exe
from the command line without any arguments.
Since you are looking for help on a match object, you can call
>>> m = re.match('a','a') #example match command
>>> help(m)