What do you need, specifically? If you have personnel interested in boiler operation, I know of a company that we use to train new operators either in classroom format or by manuals.
Most governmental jurisdictions require trained and licensed Boiler Operators. Check with insurance provider.
The boiler manufacturer should have instruction manual for items specific to the boiler. In the extreme case, think of what instructions and training would be involved with a nuclear powered boiler.
"Low Pressure Boilers", 2nd Edition, by Frederick Steingress
"High Pressure Boilers", 3rd Edition, by F. Steingress, Harold Frost, Daryl Walker
"Stationary Engineering", 3rd Edition, same 3 authors.
Pluse Boiler Operation Video series, "Boiler Operator's Workbook", etc.
All this from American Technical Publishers, Inc.
I've worked in and around power houses for almost 30 years, and have acquired quite an extensive library spanning the later 1800's through to recent publications, and the SAIT (Southern Alberta Institute of Technology) mentioned by GLWells really are the best. Alberta spends some of the zillions of dollars they rake-in on oil & gas for construction & industrial trades training, and arguably has the best apprenticeship training programs on the planet. (Note that I don't live or work in Alberta, and never have.)
It does my heart good to hear my alma mater praised so highly ^___^ We're called 'power engineers' because we *are* trained to engineer, not just to operate. Power Engineering in Canada is a laddered syllabus combining hands-on experience with schooling - most certificate exams are two or four parts, and you can't take the last exams until you've completed the required hands-on time, usually measured in years. So by the time a power engineer has achieved the covetted First Class certificate, s/he's accumulated close to twenty years of experience and schooling and *really* knows what s/he's talking about!
I'm still low on the ladder but I've done some HVAC and piping design work and am currently planning the repiping of a hydronic boiler. Fun and feels good (especially since I'm correcting someone else's mistakes ^__~ ) Every school likes to claim "oh yeah we're the best", but its really good to see those claims supported!