wordpress on localhost lamp doesn’t let me install plugins

i’ve installed a LAMP server on my ubunutu 11.04.
i’ve installed wordpress and hooked it right with the MySQL db.
i’ve changed the permissions of the www-data group to read and write files.

every thing is seems to work and i can manage the site through the admin panel, but i can’t install plugins cause the system is asking me the FTP details, and i can’t seem to go through it.

can any body help? please…

I usually do this when that happens (only locally, not for production) :

chown -R nobody:nobody /path/to/wordpress