I've found this following method very good:
You can leave the battery in, that extra weight does not add to the shipping price.
If there is no hard disk, just put the HD-cover in (if available).
Wrap the TP tightly in bubble wrap (big bubbles preferred) with enough extra on the short sides,
so that it will just squeeze in the standard flat Priority Mail Box O-1097 from USPS.
Dimensions: 11-1/2" x 13-1/8" x 2-3/8"
Put in an extra rolled strip of bubble wrap to fill any leftover gap along the long side. Close the box.
Put this box inside the slightly larger flat Priority Mail Box Flat Rate Box-O-FRB-2 from USPS.
Dimensions: 11-7/8" x 13-5/8" x 3-3/8"
It's a tight squeeze, but it fits.
This laptop now has an extremely sturdy packing, and there is really no need to use special laptop boxes (unless you have a money tree in your garden).

Both boxes are available for free from nearly all US Post Offices.
[Note: if you are an eBay shipper, you can order those boxes online free in packs of 10 or more, shipped free to your home].
You can ship the laptop now via Priority Mail Medium Flat Rate to:
Anywhere in the USA: $10.95
Canada and Mexico: $27.95
Rest of the world: $45.50
[EDIT: prices correct as per 11/4/2011]
Don't forget to insure the package!

Ship the AC Adapter and whatever else you have in a separate small box.

For details on available boxes, see this USPS webpage

Preferably insured, with tracking number, too!

Priority mail automatically gives you a tracking number, easier even if you order your postage directly online from USPS.

Insurance goes without saying!

Hey, my post office has been making me buy the extra tracking number slip whenever I ship Priority Mail. Have I been getting ripped off?

If you print your shipping label online, than tracking number is included. If you ship using the customer counter, than you need to buy the tracking number slip separately.

-- Andrey

If they charged you for it, they rip you off AFAIK.

Just sign up with USPS.
You can pay them with a credit/debit card or even PayPal.
Then order your postage online, print out the label and stick it on your package.
From about $15.- onwards you even get a discount!
You get en email confirmation with the tracking number. You can also have them send that info to the receiver.
Best of all, you can ask them to collect the package from your house for free, you don't even have to go to the post office yourself.

You can also order boxes and other things from them for free!

Ah, good to know. Thanks for the info, I think I'll look into that. With the amount of shipping I do that might save some cash.

Nice

just to let you guys know:

UPS (in Germany at least) seems to offer special Notebook-Transportation boxes that have an elastic slide-in for the TP which holds it to a cardboard. This cardboard can relatively freely "swing" in the box and will therfor absorb shocks.

It is actually a cardboard-plate with a stronger elastic foil around that is open on two ends where you enter the notebook but the foil is so strong and elastic that it shapes around the notebook like a second skin.

Also for the accessories like power, there are niches.

It is a perfect "patent".

Mayby you ask UPS for it.

Cheers
jwege

UPS "offers" them, but you have to pay for those boxes on top of their shipping charges.
USPS gives those boxes for free!