The answer?
And this might shock you - those of you who know what a die hard "film guy" I am...
Photoshop!
Infrared film is prohibitively expensive, getting harder to find, and is a pain in the ass to meter, focus, and develop with a acceptable level of grain...
Shoot with cheap color film, expired, the cheaper and crappier the better - doesn't matter...
Read this site, and load the set of 6 Actions at the bottom of the page (free):
http://www.nickgallery.com/web_pages/technical 20.htm
Love the "IR" look. But when it boils right down to it, IR is just an "effect". To get this effect "in the camera" you lose control, it's expensive, there's a high "spoilage" factor, and it's an overall pain.
Shoot with cheapest, expiredest, color film you want. 800 speed if you want! Use whatever camera or focal length you want (not the one you happen to have a pricey IR filter for...) Use whatever format you want - 135, 6x6, 110 - whatever.
And shoot "in the winter" on dark days or indoors - where there isn't much "IR" light. Take a pic you "wish you had shot in IR" or "think" would have made a great IR shot, and scan it in, and "IR" it "in post".
And "Photoshop" it...
Sorry, I may be a purist, but sometimes the pragmatist in me trumps it. A "so-so" quicky sample is below. Use the "make sample images" action that will make six small "try it out" images labeled for the corresponding action and try each of the six different IR actions. Pick the one you like the best. A few of the actions work with black and white. Or use combinations.