How to become an effective leader?

[Betty]

I've been asked to let my inner leader out at work... I don't have a manager title. I'm the only one in my two departments (yeah, I'm a busy girl). I can tend to come off as a know-it-all. (I know this about myself but am so far unable to conquer this entirely. I don't think everyone thinks this about this however. Guess it's all in your point of view.)

Bottom line is - I need help.

If I want to continuing climbing in my career, and get a raise, I need to begin showing some area of management or leadership without my coworkers thinking:

1. She's not my boss! Why is she acting like some sort of leader around me?

and/or

2. Coming off as a bitchy know it all.

I get along well with my coworkers who all tend to get along well with each other. My position requires a work independantly quite a bit, but also work directly with others in a computer support manner.

I'm looking for ways I can improve my skills in this area. Book suggestions perhaps.

Or other ways if you've got some ideas.