Here is some info on one way to use an analyzer -
http://www.prosoundweb.com/install/sac/n26_4/zrta/zrta-1.shtml
Here is a reasonably priced (haven't used it ) software analyzer - ($300) there is a free demo, and an FAQ to read.
http://www.7shades.com/soundprism/index.html
RTA's (Real Time Analyzers) can also be used to "tune" not a room, so much as a "listening position" - keep in mind that no two spots in a room will sound the same as far as frequency response. Especially true of rectangular rooms (no splayed walls, no vaulted ceilings) - the primary resonances of a rectanglar room are decided by the dimensions - whatever those dimensions are, each will cause a base frequency to resonate. Each of those dimensions' resonant frequencies will also be accented at 2x, 3x, 4x, etc, the frequency.
At the base frequency (the lowest resonant freq for that dimension) the sound pressure will be greatest at the walls (or floor and ceiling, in the case of the height measurement) at the midpoint of any dimension, that dimension's base freq. will have the LEAST sound pressure. The 2nd harmonic will also have maximum pressure at the center, but the THIRD harmonic will have MINIMUM pressure at center, and MAXIMUM pressure at 1/3 and 2/3 the dimension. This gets even more complex when you throw in tangential and oblique modes.
Before this gets at thick as the books it comes from, the main point is that a room is very complex in its reaction to sound. Every time you move either a sound source OR the listener, things change.
Sooo, in order to use an analyzer to "tune" a room, you need to learn what you are looking at and how to correct for it - sometimes just moving the desk/nearfields/ears 6 inches front or rear can change everything.
For a tracking room, this can be even more fun. Where do you put the instrument, then where does the mic go, etc? For example, you are dealing with THREE dimensions, but most beginners NEVER think of raising or lowering the mic or performer. (Consider a 6-foot vocalist in a room with a 12-foot ceiling - can you say "null"?)
Also, if you were to use one of the consumer type combo graphic EQ and pink noise generators and "tune" everything "flat", you would think it sounded crappy. Look up "Fletcher-Munson" on google or AskJeeves - you will find out how "not flat" the human ear is, and hopefully why it is best to always mix at the same SPL.
This is getting long winded, even for me - I hope this helped some... Steve