Inexpensive rack mount 2.4KW dimmers are available from Lightronics. I've toured with them and though they seem kind of low end, they held up just fine.
http://www.lightronics.com/rackmounts.html
Inexpensive PC DMX interfaces= $60 and free DMX contsoftwareYou can get a $60 USB DMX PC widget from http://www.enttec.com and you can download free public domain open source software from the website. Complete info on writing your own software for use with this widget is provided including...
Inexpensive PC DMX interfaces= $60Buy a PC USB DMX interface here for $60:
http://enttec.com (click on Open DMX USB Interface)
Free lighting control software also on this site. Also info and source code so you can program your own in Visual BASIC or C++ or Python or ???