BoeingBoy, I'm just finishing up my five weeks of beam radiation treatment (one treatment left on Monday). The treatment itself is pretty much a non-event - basically laying still on a table for ~10 minutes (there's not physical sensation associated with the treatment). But there are side effects. Based on my conversations with the doctor mine sound pretty typical - annoying but not horrible. Most noticeable (and annoying) is that I need to pee and poop a lot - roughly twice what was normal pre-treatment. Apparently the treatment irritates things and they don't work as well, plus the bladder becomes more sensitive (good news is that if a bathroom wasn't convenient, holding it was still possible - just unpleasant). If you have issues with constipation, you won't during the treatment... Also a definite lack of energy and a general achy feeling.
I get a month off, then they'll implant the radioactive seeds in early June.