you don't have to have a compressor...if you are cheap like me you can us a breaker bar w/ a extension...that will break it off easily depending on how long of a extension you use...you also need a way to lock the crank down...you can either use a pipe wrench on the crank pulley or use your battery tie down to lock flywheel...
http://hybrid2.honda-perf.org/tech/headswap/07.html
i actually have a impact wrench and it doesn't work as well a big breaker bar...