For such of those you intersted in getting a good ( free or low cost ) Windows based IDE for creating your assembly programs, here are some tips:

(For such of those not using the Keil assembler )

1. Download the ASEM51 from here :
http://plit.de/asem-51/home.htm

2. Get a free editor or a shareware editor from the web. One such thread in this forum gives many such ideas:

http://www.8052.com/forum/read.phtml?id=13337

And also this :

http://www.8052.com/forum/read.phtml?id=66908

Configure the editor to assemble using ASEM51 using its command line options. Thats it - you have a decent coding setup to start with.

I personally can suggest the MED editor ( www.med-editor.com ) with ASEM51. Nice combination.

Raghu