Heh, I just got to it
Yes, it is possible to install it on a primary partition, in fact, required if you are going to have it the active OS.
I'm not Linux expert, so I can't really tell you how to install it, though I think it should be a easy as installing Windows is (just use the install disc and set the correct configurations).
If you are trying to install it on a serial ATA drive, then you will have to get the correct drivers to Linux recognizes the drive and then (if Linux doesn't do this automatically) create a dynamic partition, then format it.
That's all I can tell you... Linux should install just fine on a primary partition (that's what you're using for any other operating system as well).