will I have any problems installing Lilo into the MBR?
 

Current setup is as follows:

NEC 3500 DVD Burner = Primary Master
160gb HD = Secondary Slave
120gb HD = Secondary Master

I have Windows XP installed into a 40 gb partition on the 160gb HardDrive. The 120gb Hardrive has nothing on it and will be installing Slackware 10.0 on it soon.

Anything special I need to add to be sure that both OSes will be able to boot?

Thanks

just do an "expert" install of LILO in Slack. start a new header file, add the linux partition, add the windows partition, and install LILO. it should be ok to just overwrite the MBR. just in case,

BACKUP ALL EXISTING DATA TO BE SAFE!

i'm sure you can find plenty of other resources about dualbooting these two OSes on the internet, especially in LQ.