recursive file editing

[TaeKyon]

I'm a python newbie; here are a few questions relative to a
problem I'm trying to solve; I'm wandering if python is the best
instrument or if awk or a mix of bash and sed would be better:

1) how would I get recursively descend
through all files in all subdirectories of 
the one in which my script is called ?

2) each file examined should be edited; IF a string of this type is found

foo.asp=dev?bar (where bar can be a digit or an empty space)

it should always be substituted with this string

foo-bar.html (if bar is an empty space the new string is foo-.html)

3) the names of files read may themselves be of the sort foo.asp=dev?bar;
the edited output file should also be renamed according to the same rule
as above ... or would this be better handled by a bash script ?

Any hints appreciated

-- 
Michele Alzetta