For knotty pine, I've read that using a washcoat of shellac before the oil will help to even out the color a bit. Do a google search on rec.woodworking and you will get some tips on how to finish knotty pine.
I've used the minwax pre-conditioner on pine before but that didn't seem to work that well. I don't use pine much and prefer using hardwoods.
Jim
www.embeddedtronics.com
PS One of my hobbies is woodworking and I have a decent woodshop to make stuff with.