The site which is operated by U Haul is useful if you would like help to load your U Crates, Pallets, or a shipping container. It covers all the USA and Canada. I believe some crews can also help you with some packing or moving heavy items like pianos as well as offering cleaning services.
You can view pricing and reviews once you have entered your town or zip code.
I wish we had a similar source to recommend in the UK and Europe. If you know of one, please let us know.