I am trying to set up a field (Lead Score) which gives my leads a numerical vlaue based on a couple  fields: Lead status & Rating...for instance if Lead status= "Nego. Contract Sent" and the Rating field = "Hot"...then this prospect would have a rating of 20 because "Nego. Contract Sent" has a value of 10 and the "Hot" rating also has a value of 10 giving them a rating of 20. If the Lead status="Information Flyer Sent" and the rating is still "Hot" they would have a value of 17 (10 for Hot and 7 for "information flyer"

I started to setup a workflow rule which said if "Rule Criteria Lead: Rating equals Warm,INTERESTED NOW,Cold,Hot" but then got stumped on the Workflow Action which I think would need to be a field update...

This is bascially what I am trying to do and I am definitely open to other options if somebody has a better way of doing this. This seems to logically make sense to me but you guys may have more experience and think of something else. Your help is appreciated!