It differs in different facilities. My facility will allow any nurse that volunteers to do it dependant on how long they have worked there (like me, I have only been there for 1 month as their employee...6 months as agency...so I am not quite up to par with them yet to teach).
Once I establish myself, they may have me take on a student nurse for part of a shift (like a first year...which I already have as agency really)...so not a full preceptor position.
I am eager to be a preceptor once I get the feel for all the bells and whistles of the facility (still have some things to re-learn for their facility policies). I love to teach and I like using humor and fun stories...so the few students I have had have had a blast with me, and learned not only their books info...but common sense nursing!!!!! It may have been 7 years ago, but I remember the feel of student/new nurse very vividly..and heck, agency can make you feel that way all over again too...so I remember, and treat accordingly big time
And YES, you get a few extra dollars for doing preceptorship and hour, so if you get a lighter load and take on a student...very worth it (if uncle sam doesn't take that extra out of the paycheck..LOL!).