Was just about to post that David may have some good pointers, then saw that he had indeed posted but recently changed his avatar
The negatives I have handled seem to have always come in either a manila envelope or glassine sleeves, with a few more recent ones having archival quality album pages (typically for negative strips). Adorama has a number of different storage options, including archival glassine envelopes in all manner of sizes. I personally like to put them in a glassine envelope and then drop that into a toploader for stability, though that added thickness adds up fast with a stack of negatives. My understanding regarding storage is that temperature and light (well, lack of light) are of key importance. Humidity can be a factor as well, though few of us have options for controlling that in our homes. I know the Library of Congress has done some research on optimal storage conditions, and may have that info on their site, though I don't recall the specs off the top of my head.
I would add that if/when you have prints made, have them do a high quality (as high resolution as they possibly can) scan so that you can do any further prints or englargements from the scan, and can also go in and clean up any scratches or other faults with Photoshop or other programs. The reason I say "scan as large as possible" is you can always reduce file size if you need to upload the scan somewhere, but if you decide to do an enlargement later on, you won't have to re-scan it to do so.
If you decide to scan them yourself, as the above poster said, the Epson V700 will handle the medium-format and larger negatives up to I believe 8"x10" size. I have an Epson Perfection 4990 that will also handle the same size range. I'm not sure what the new retail price is on those, but you can find them somewhat frequently on eBay in the $400 range, or maybe a little cheaper if you don't need the film holders/guides. If you decide to go that route and have trouble finding a scanner, let me know as I have a "back-up" 4990 available (don't really use the main one enough to justify keeping a back-up
).