As far as weight loss goes... when I first started road biking, once I was comfortable in the saddle, I forced myself to tackle hills that I didn't really want to. Makes for great interval training if there are hills in a sequence. Alternately you can sprint hard for a minute and rest for 2 or 3 and do that. Make sure you properly fuel for your ride before and get some good carbs in and then immediately post-ride (within 30 minutes) have a carb/protein rich snack. It worked wonders for me last fall and back in Summer 07 when I rode about five days a week.

The hills WILL get easier every time and you'll feel really good about that. I promise!