the lowers aren't really serviceable. if it's the uppers squeaking - then I would put on some aftermarket upper control arms (like the SPCs - which have serviceable/replacable balls).
{EDIT - oops, didn't see what forum this was as it came on email. below was on my 100 series. Same advise applies to bushings tho}
FWIW, my squeaks were thought to be ball joints were actually the drop link bushings on the sway bars... and the lower arm bushings. they just dried out.
I ended up replacing the lower control arms with OEMs at 250k miles and due to some dumb-understanding of an inspection station in MA, had to install new upper balljoints last fall -- so was happy I had SPC's . While they were in there I had them put in some fresh OME shocks and she rides tight again.