Found the name of knee injury I have: Iliotibial Band Syndrome (ITBS). There's even a itbs.info site on it and, linked off, a fairly comprehensive description of the syndrome. Basically, tendon gets really inflamed and everything goes kaput. I still shouldn't run though, which is extremely disconcerting. Last long run was 16, and I have 2.5 more weeks before the marathon and I haven't run in about a week now. I think my only bet is to just run very slowly (10:00/mile even at the beginning. No more 9:00/mile for the first 7 miles) and run a lot starting this thursday and leave the last week for tapering/rest. Very very nervous...