Starting problems

I have a 1998 Honda accord EX. It has about 160,000 miles on it, manual transmission and a 4 cylinder engine. Recently I have found that occasionally when trying to start the car the key will not turn. This has happened several times over the last 3 months and I find that if I sit and jiggle the key, after many minutes It will sometimes turn. Once the key turns the car starts no problem. The steering wheel is not locked and I have tried using a spare key to start it in case the key has worn down. Neither key turns. I used some WD-40 the first time this occurred and it solved the problem for a week or two. I also notice that it seems my brakes have locked when this event occurs. Any ideas as to what may be causing this problem?