There are 3 basic types of film:
Black and White negative (needs to be processed in black and white chemicals, and the film comes out backwards - like pressing the 'invert' button in photoshop)
Colour negative (generally needs to be processed in C-41 chemicals - any photo lab can do these. colours will be inverted.)
Transparency (also known as 'slide' film since they are usually seen mounted onto 'slides' so you can view them on a projecter - needs to be processed in E-6 chemicals, not many places do these, but when viewed, colours are as you would expect them to be.)
35mm (135 in some places) is for 35mm cameras
120 is 'medium format' - the stuff you've thrown yourself head first into. This is nowhere near as universal as 35mm - you'll need to take it to pro labs to get developed, especially black and white negative and transparency (however those two are the best types

) - colour negative (C-41) 120 film can be processed at Jessops, however they can't put it onto a CD for you.
Step 1: shoot
Step 2: develop film in total darkness (either at a lab or at home)
step 3: scan or print (either on a computer with a decent flatbed/drum scanner or in a darkroom)
Gary, if you've never been in a darkroom, I seriously recommend you find one to go in.
Nothing I have used has matched the sheer pleasure from printing your own photographs.
You find yourself really
looking at your photographs, rather than scan, upload to flickr, get slated on here for technical inadequacies, and then shoved to the back of a harddrive never to be seen again.
Film is a whole different experience to digital, they could almost be divided into two separate hobbies, however the results are no where near instantaneous. It takes a lot of time to even get a print from film, but my god is it worth it.