Since I have recently been working on a BizTalk 2002 project I thought I would write a little bit about the major differences and how to perform certain tasks that I've forgotten over the years while working on nothing but 2004 (I've been spoiled).

I'll start with the list of usable MACROS (or symbols in the help file):

%datetime%             Date and time, in milliseconds, of the file creation. The time is based on Greenwich Mean Time (GMT) rather than local time.
%document_name% Name of the document definition used to process the source file.
%server%                Host name of the server that processed the document.
%src_filename%      Name of the file that is being submitted for processing.
%tracking_id%        Globally unique tracking number.
%uid%                    Counter that increases over time, represented in milliseconds. This number is reset when the server is restarted.

That's a start and there will be more to come as I remember more BizTalk 2002 tips and tricks.