Anyone drive gear from Canada to US?

I have an opportunity to deliver to a buyer just across the border. What paperwork do I need to make it go easy and do I have to contact anyone before hand to avoid any delays?
I have brought stuff I bought in the US to Canada but I have never carried anything over to sell.
Thanks for any advice.
I was just at the Point Roberts/Tswwassen (Vancouver) border. I asked the US border patrol officer the same question.

According to him, you have to go into the office and declare it. There is a $10 or $11 charge.

If the good is produced in either of the NAFTA countries than there is no additional duties or taxes..... however I think this is dependant on the value of the good in question (he made a note of asking me the value before he stressed that the good had to be made in a NAFTA country.

Hope this helps.
A word to those crossing the Canadian/US border.

I live within 40 minutes of 3 bridges to Canada and the inspectors and customs officials are very serious. There was a time, before 9/11 basically, when customs at the border was primarily a formality.

No longer. Most of the agents are carrying weapons; vehicles and passengers are scutinized very closely. Make sure you have proper documentation for yourself, passengers, and vehicle. Don't try to hide anything or deceive the inspectors in any way.

It can be a real nightmare.
As Elf73 suggests, it's very important to be able to document that the gear was made in a country covered by the NAFTA agreement (which would almost surely be either Canada or the U.S. if it's audio gear.) If it's not, or you don't have some proof of it, the delay can be substantial.

I brought a pair of ProAc speakers, made in England, from British Columbia into Washington state and spent at least 45 minutes trying to help the customs agents find the right line item in their catalogs listing what looked like tens or hundreds of thousands of foreign-made products. After all that, the assessment of $54 in import duty seemed almost completely arbitrary and I was glad to pay it to get out of there.

The agents were very nice and really were trying to do the right thing but the process made me realize if I were to do it again I'd make sure I was buying something that didn't require that procedure.
One of my first purchases on AudiogoN eight years ago was from a guy living in Canada. He drove the amp from Quebec into NY and shipped it to me from there.

Boy, those were the halcyon days, eh?