Speed advice?

Situation: I am still overweight (about 80 to 90# above where I want to be for running), and I am slow (race = 12 min/mile; training = 14:20 or so per mile). It is also getting ready for snow to fly. I am running my first marathon in May of 2007 and if I continue losing weight at the rate I have done for the last 90 days, I will be at target weight next July/August.

My current thinking is that I continue with endurance and mileage work and not worry about speed. I feel this will lower my risk of injury and help me with my marathon goals in the long term. This does mean that I am looking at a 5:50 to 6:20 time for my first marathon. I will start adding speed work in the spring when I can get on outdoor tracks and my weight is down lower.

I am open to advice on this; please chime in with emails and comments!

Thanks.