Some Jcs.Ref tutorials:

http://www.jazz2online.com/~jcsref/n...=index&mode=id - masking in general
http://www.jazz2online.com/~jcsref/n...=index&mode=id - compiling a tileset
http://www.jazz2online.com/~jcsref/n...=index&mode=id - converting 16 bit images to 8 bit

Keep in mind this site is not finished yet, so.. don't be too flabbergasted by all the unfinished stuff and the lack of articles ;p

J2o has some tutorials in www.jazz2online.com/articles/