Baddabob. There should be a customs office in every city. But shippers like DHL, Fedex, and UPS have their own brokerage agents, which I don't think you can bypass. Industrial shippers (not sure if this is the right distinction) like BAX Global do not include their own brokerage agents and so you have to go to customs yourself (BAX can only be used if you have a business account while Fedex and UPS have size limits as well as getting too expensive for large/heavy items, so the choice is often made for you). Keep in mind that you have to run around (from shipping company to get the required forms, to the customs office to clear the shipment, then back to the shipping company to arrange for pickup/delivery) and will most likely have to wait in line at the customs office, which may not be worthwhile for small ticket items. I recently had to go through this process to pick up my amp. It was worth it for me as it was a big ticket item. But since it was my first time, all that running around as well as waiting in line was a big hassle and a big waste of time (It was too heavy for me to pick the item up myself anyways, so my 1-2h time was spent clearing customs).
As to the original question. There should actually be a place on the form to mark whether the shipper or receiver is responsible for taxes and customs.