46Driver,
None of the majors count helo time toward minimum qualifications, and unfortunately I don't think that any company does. Here are FedEx qualification requirements from the website:
1500 hours total fixed-wing time as pilot-in command (PIC) or first officer (SIC) including a minimum 1000 hours PIC in fixed-wing jet, fixed wing multi-engine turbo-prop, or multi-engine recip over 20,000 LBGW or combination thereof.
Note: PIC for this purpose is defined as Captain/Aircraft Commander of record, not simply the sole manipulator of the controls.
Note: FedEx considers only pilot time in fixed wing aircraft toward minimum qualifications. This does not include simulator, helicopter, flight engineer, bombardier, navigator, RIO, EWO, WSO, NFO, or Special Crew
The bottom line is you will have to get the minimum quals somewhere, then your helo experience will be valuable on an application. I think a great resource for you would be the APTAP website, I ran across it during my job search. It's "Army Pilot to Airline Pilot"-www.aptap.org. Obviously these are predominantly helo guys and have developed a network to help other guys make it to the airlines, it was founded by Army guys but they welcome all military and seem like a great group with great resources. I didn't spend much time there but I think there is alot of really good info, I think the grand majority of these guys get the minimums to get on with a commuter (lower min qualification times), then work their way up, many have been very successful.
If this is what you really want to do, go for it, but realize that if your goal is a major airline and all your time is helo, it may be a long road to get there (and oh by the way, the commuters don't pay much). Let me know if you need any more specific info or if I can help in any way.