Front Crank Seal (oil leak)

I'm taking out my front crank seal this weekend, theres a ton of oil all over the bottom of my tracker, it starts from about the middle of the crank and goes down. I've heard that it's probably the front crank seal, or the oil pan seal. Anything I need to know before I do this?

I'm also replacing my rad and water pump, so I figured this would be a good time to get the oil thing taken care of.