Thank you all for your considered and informative replies.
I have the grinder already and I use it a lot. I prefer to grind a visible cut of meat rather than buy pre-prepared mechanically scavenged face meat or assorted left over gristly (?) bits.
It's not that I'm against gristle. The French andouillette sausages are one of my favourites. I am interested in making my own flavoured sausages such as pork, apple and spices, or maybe something weird like turkey meat with chicken heart.
That Nosso Talho looks interesting, but is over one the other side of the city to me. The Danforth is on my doorstep - although I have never been to Jerry's. I'll give that a shot.
Now the subject of fat. There is a constant battle in-house between the flavour advocate (me) and the health-concious evangelist (her). I always keep pork and duck fat in my fridge from rendering down the carcases. I have to sneak them into my recipes. Curries are always good for this, but sausages may also make a reasonable vehicle for culinary deceit.
At Jerry's, you can also buy some lamb casing, which is thinner, if you want to make breakfast links, barese sausage or merguez. It's considerably more expensive, though. And I buy my pork shoulder from them too just to give them more business than some cheap casing. You'll see as they uncoil it, there's a bit of effort involved for a small amount of money.
I've made a few different kinds. Pork with all sorts of flavour combos. Lamb is great, duck too. Chicken hearts would definitely be taking it another level.
I have the attachment and it's great. As mentioned though, you can't just buy it and figure you're making sausage. You need the grinder attachment too.
I buy my regular casings at Highland farms. You can get your pork there too.
I also like to make turkey sausages. Add a fair bit of water to the mixture if you're trying to keep the fat content down. They'll be too dense and hard to stuff if you don't. They take a long time to cook too.
1) You can usually get them at any decent butcher shop. You need more of an old school one. Italian or Eastern European would likely have them. Just ask. I go to Jerry's Supermarket on DAnforth between Greenwood and Coxwell. I've tried at a few of the yuppie butcher shops closer to home (Rowe Farms, Blackstone) and no dice. To me, you're not a real butcher shop if you don't carry stuff beyond just the prime cuts of meat. In fact, I'm going to rant about it on a separate board.
2) I've got the kitchen aid attachment. It works well. Like Mila says, keep the pressure up and they fill up nicely. By pressure, it means keep the casing taut while its filling with meat. Once you're set up, it's pretty easy to make a bunch of sausage in a short timeframe.
Also, for the kitchen aid, you'll need both the grinder and the stuffer. Not sure if you have the grinder. That's the more expensive bit, but also great to have for grinding meat for burgers, chili, etc. I use it all the time. The stuffer's only $20. Other than Williams Sonoma, it's at the Bay, but they don't carry it too often. Cayne's Housewares has both at a good price.
Oh, and as Mila mentions, don't skimp on fat. I made some batches with just pork shoulder and they were too lean. YOu need actual pork fat. I got some for free at T&T.
Sausage skins are pretty widely available.
I buy them at Nosso Talho. http://www.nossotalho.com/home.php
I bought the attachment at William Sonoma, which had quite a decent price, suprisingly. It's all about the pressure with sausage making, getting the perfect fill, not too tight, not too loose. Also the fat, don't skimp. It is really a 2 person job with the Kitchenaid.