Version 1 supported only memory
Version 2 supported 16bit transfers
Version 5 supported 32bit transfers
Type 1 2 and 3 refer to the size of the card. Type 1 being the smallest and type 3 the largest.
All are backwards compatible so you can fit a Version 2 type 1 card in a Version 5 type 3 slot.
The latest notebooks with the Intel Core-Duo CPU have Express Card slots. These are not backwards compatible with PCMCIA.