Where do you go to get Double Boxing Services?

Was looking to find out where/how people handle boxing and double boxing. A couple of a components I plan to list for sale were bought back when I didn't think I needed the original boxes. Now, I want to sell them, but was wondering about where people go to get them boxed. I live in West Los Angeles, but I'm sure anyone could have a good idea or two on how to handle things properly for our buyers!
I use Mail Boxes Etc. The one time I've had to report damage they were/are more than helpful. They are insured on top of whatever insurance you purchase from uPS/Fedex/ They are authorized packers (trained by UPS) so they know how to properly pack items of all weights and sizes.
I live in the LA area too and always use Mail Boxes Etc for double boxing. Their service may cost a bit more, but the piece of mind I get as a seller is worth it.
Mailboxes has worked for me. Cost about $15.00 for box, foam, and labor, plus additional charges for extra weight. I've never used it, but I understand they have additional insurance.
Vik, Gunbei, Swampwalker,
Has anyone used this service to send large speakers over long distances via UPS?
Another vote for Mailboxes etc.--they have been very good at packing some of the larger items I've shipped.
Judit, I've never had to ship large speakers. I would probably try to replicate the original shipping carton, but I realize that can be quite expensive. Although my 73 lb. ATI 1505 came in a double thick cardboard box, I would think anything over a 100-150 lbs. might require a wood crate. Yikes!