Also: if you are at all handy with max/msp, there is an external called IRmeasure~ as part of the HISStools collection. This object gives you some flexibility in the type of impulse you can use, either an ESS (exponentially swept sine wave), a burst of white/pink noise etc., with complete control over the various aspects of the impulse - attack, length, spectral range, decay. The impulse is measured using a speaker(s) and microphone(s). Once you have a IR of a space you could ostensibly use it in other IR verbs or use with other HISStools objects like their multiconvolve~, a zero latency deconvolution reverb. It is truly nice! And free!
Here is a link to the Huddersfield website: http://www.thehiss.org/
Here is a link to a web-post about how to use the external: http://m.youtube.com/watch?v=0waUi6qpf-k
I have used this object to take impulse responses of auditoriums, stairwells, a long hallway, or less conventionally for creative equalization to approximate the sound of being inside a closet while listening to something in another or room. Other fun things to try were pieces of analogue gear, tape machines, digital delays, effects pedals, a channel strip... Really anything you can put a signal through has an IR!