So i've owned '46 for a long time (retail), and have never really known how to use multiplayer
Should I use xfire or what, and if so, how does it work?
I know that this should be in th Il-2 thread, but there might be some more options from other people...

Xfire is the best way to get a game going with IL-2. I know quite a few people here use it for that game in particular.
Not sure if Gameranger supports it, but GR isn't a bad service provided others use it too. And if it even has the game.

I thought the IL-2 multiplayer community mostly favored HyperLobby.
(If you do take that route, make sure to select "IL-2 Forgotten Battles", as that's what covers the 1946 release here on GOG.)

Seconded. Hyperlobby is definitely the favored matchmaking software for the IL-2 community. I've played IL-2 almost exclusively multiplayer for a long time, and Hyperlobby was all I ever used.

Hyperlobby is the way to go. I played IL-2 multiplayer a lot a year or two ago, and there were a lot of people playing.
There are many different styles of servers, ranging from "arcade" (no cockpit, choose just about any plane, labels on, just go blast stuff) to "full real" (all the realism switches on, objectives, teamwork encouraged), so find one that fits your style.
Many of the servers, especially the more realistic ones, use Teamspeak extensively, and I strongly recommend it as it adds a whole new dimension to the game.

Thanks guys
EDIT: I'm now playing online using hyperlobby and it's really good. Despite this, I still suck!