Several hotels do the park and fly rates, which include your 1 night hotel stay, parking for the duration of your trip (# of nights vary by hotel) and complimentary shuttle to and from the airport.
We use the Sheraton and Wingate by Wyndham alot for our clients.
The Fast Park is also an excellent option and highly recommended over the long term lots. They pick you up right at your car, help you with your luggage and drop you back off right at your car when you return. No searching for where you are parked! They also do have a limited number of covered spaces.
I use the blue lot myself every time I fly out.
Can anyone recommend a park and fly at BWI? I'll be gone for a week. I have an 8AM flight.