I recommend AMOS Pro 2.X (up to 255 banks, in theory).
As for help, you'll find plenty of AMOS help here and at these sites:
http://www.liquido2.comhttp://groups.yahoo.com/group/AMOS-LISTIf you have programmed in BASIC before, many of the main commands (PRINT, PLOT, CLS etc.) will be familiar

I do also own a version of Blitz Basic (plus a photocopied version of the manual), but it seemed a little too complicated for my liking.... but by this time I had already been playing with AMOS/AMOS Pro for 4 years.
Regards,
Lonewolf10