So do I just mail out copies of the FFL, or is there a special address for each distributor to send it to?
Most accept fax copies.
Make a bunch of copies of the license when you receive it, and sign them.
If a dealer needs your license with an original, inked signature, mail them one.
Don't do as I did, and sign the original you receive... I still gotta send in $1 and tell them my dog ate it.
Some companies, such as Midway, offer dealer discounts with your FFL. Sometimes that can save you $$, though Midway's pricing of late is getting way out of line.
If you reload, Graf's will give you a dealer account as well, and their pricing is pretty tough to beat. Gotta meet a mimimum annual $$ amount to keep the discounts, though.