Hi Chris,
The shutter speed of your Brownie is going to be somewhere around 1/30th of a second (not an exact figure by any means, more a reasonable assumption that seems to work). That's pretty slow, so you don't want to use too fast a film unless it's quite gloomy. For a first roll I'd use 100, and wait for reasonably bright light. Or, if you have a light meter, set it to 1/30th and f10 and see how often it is bright enough to shoot. I wouldn't try 400 for starters, as it's too likley to terminally over-expose. If you've got a model with the lens behind the shutter, you could even try colour film - there's so much camera preventing unnecessary reflection on the lens that flare is unlikely to be a problem.
You also need to remember that that same slow shutter speed makes it awkward to hold still. I find the best way to keep it still as you press the shutter is to prop it against my belt. However I'm slim so less-waif-like shooters might have to modify the method...
Good luck, and show us the pics!
Adrian
