Digital BW, The Print

I'm new to digital printing and I'm curious as to the effect of the DPI 
setting on print quality when I convert my RAW files for CS2.  I've 
read here and there people setting 360 or 720 or whatever.  Is that the 
optimal DPI and why?  I have a fair amount of book knowledge on the 
subject but I'm still not quite catching the relationship between Epson 
printers, 720/360 dpi, and print quality.

I think it's because the "native" (if that's what you call it) DPI for 
epson printers is 720 and 360 is half of that so that kinda makes sense.

Thanks for any info.

Brian Skipper