Hi,
There are three tunings for pedal steels which are commonly used:
E9 ('Nashville'
tuning - F# Eb G# E B G# F# E D B - this is the tuning which is generally used on country records, and is the tuning that most 10 string single neck instruments are set up for.
C6 tuning - D E C A G E C A F C - this is usually used for jazz, or blues, and found as the second neck of a ten string double neck guitar.
B6 'Universal' tuning - F# Eb G# E B G# F# E B G# E - this tuning incorporates the features of both E9 and C6 tuning, and is found on 12 string steels (there is another tuning called Extended E9, although this isn't as flexible as B6).
On an E9 neck, there are usually three pedals - one to raise B's to C#'s, one to raise G#'s to A's, and one which raises the top E to an F, and the top B to a C#. In addition to this, there are usually four knee levers, one to lower the E strings to Eb's, one to raise the E strings to F's, one to lower the Eb to a D, and one to lower the F# to an F.
If you already play guitar, there is a useful video available from Carter steel guitars:
http://www.steelguitar.com/resource/videos/
vids6string.html
which shows how an E9 steel relates to a six string guitar.
Best Wishes,
