In case you just want to view them, have a look at http://petapixel.com/2015/03/22/how-to-turn-an-ipad-and-iphone-into-a-negative-film-viewing-station/ for a quick solution (of course, you can use other light sources, etc., but the general idea is the same). For positives, there used to be dedicated slide viewers and slide projectors, but mostly for smaller medium format slides like 6x4.5cm or 6x6cm. I have never seen viewers or projectors for 6x9cm slides, but they do seem to exist (see, e.g., http://photo.net/medium-format-photography-forum/00SbW4 ) and you can probably find them second-hand from the usual sources.

In case you want to make (digital) prints with your printer, you need to scan the negatives first. There are three basic options:

• dedicated film scanner: I don't think (affordable) dedicated medium format film scanners are readily available any more (and once they were more readily available, they usually only have covered formats up to 6x6cm or 6x7cm). However, you might be lucky getting some second-hand option (beware of compatibility problems with modern operating systems, though) or, if money is no problem, some professional grade equipment.
• flatbed scanner with support for film scanning (i.e., with backlight and film carriers): There are various options available, you just need to make sure that the scanner actually supports your film format (some just provide enough backlighting for 35mm film). If you happen to already own a scanner, but without support for film scanning and you don't mind some simple crafting, here's a nice trick on how you can use it to scan film http://makezine.com/craft/how-to_turn_slides_and_negativ/
• a camera: You can use a setup like http://petapixel.com/2013/03/25/digitizing-your-film-using-your-dslr/ or http://petapixel.com/2012/12/24/how-to-scan-your-film-using-a-digital-camera-and-macro-lens/ If you already own a suitable camera, this probably is the cheapest option, but will also require the most amount of manual work.

Regarding scanners, see also Medium Format Scanner. Scanners also typically come with some software for automatically converting the negatives to positives and might also have some support for image enhancing (e.g., dust removal) depending on the film type.

Of course, you can also try to get a good old enlarger (again, make sure it supports medium format film of your size) and make some actual prints, which is a lot of fun. Alternatively, as Blrfl points out in the comments, there should also be some labs around that still do prints from