What kind of shoes are you using? When I had aliums (using XE and XS now) the hard rubber treads on the sides of my mtb shoes would rub against the platform section of the pedal and make a good bit of noise. It may have been the combination of the specific rubber compound and the aluminum body, but it was pretty noisy, especially when wet. I found rubbing a bit of wax on the platform section made the noise go away for a few rides and didn't really have any effect on the feel of the pedal.

+1 on what others have said about wet lubes on the inside of the pedal and dry lubes on the outside.