Code:
shell# find /some/folder -type d -exec chmod <blah-blah> "{}" \;
The above should work fine enough.
Replace
/some/path with whatever is the start directory to recurse into; replace
<blah-blah> with whatever read/write/whatever permission(s) you wish (refer to the chmod man page).
-type d ... this means find items of the type "directory" (refer to the `find` manpage for full details).
chrism01 neat me to it -- well, there you have it.
Sasha