One word for "bringing someone up to speed"

Onboarding

Wikipedia defines this as

The mechanism through which new employees acquire the necessary knowledge, skills, and behaviors to become effective organizational members and insiders.

"She has been tremendously helpful onboarding the company's new employees."

In my experience this term is very common in the HR field and is often used during the new hire process. My view of onboarding includes any type of activity or process that is aimed at preparing a new employee for his/her position. It can include training, getting certifications, briefing on policies and so on. I assume the process varies widely depending on the position and field of work.

Briefing is a good one.

http://dictionary.reference.com/browse/briefing?s=t

2. any set of concise instructions or a summary of events.

However, it may be too authoritative for your purposes.

Inducting

Oxford:

induct: Admit (someone) formally to a post or organization

Wikipedia:

An induction programme is part of an organisations knowledge management process and is intended to enable the new starter to become a useful, integrated member of the team, rather than being "thrown in at the deep end" without understanding how to do their job, or how their role fits in with the rest of the company.

acclimate: to accustom or become accustomed to a new climate or environment; adapt.(Dictionary.com)

The difference between "accustomed" and "acclimated" is that "accustomed" is familiar through use; usual; customary while "acclimated" is accustomed, adapted, or hardened to some environment. (the-difference-between.com)

She has been tremendously helpful in getting the company's new employees acclimated.