What salons are knowledgable with cutting hair for donation purposes?

Any of them.

The donation process is extremely hard: they put your hair in ponytails, cut at least ten inches off, stick it in a bag and send it in. It is so hard, in fact, that someone on their first day of beauty school can do it. You can do it yourself, but most people who donate their hair then get a cute short haircut.

And...the Locks of Love people have sent the instructions for handling donated hair to every salon in America.