I started riding for work and errands during the summer - July, I think. I haven't lost any weight (haven't been able to convince myself that losing weight is worth giving up soda) but I'm still way healthier than I was!

The biggest changes I've noticed:

More happy days, fewer depressed ones!
Better wind
Stronger legs, hands, and back

Also, a nice side effect of using my bike for errands is that I can't buy as much crap at the store