[cars]

Originally Posted by watermark

becoming resentful, competitive, spiteful

As others have already said, you do have alternatives, if really that disatisfied! In today's economy, most are happy to just "still" have a job!

Not paid enough by whose standards? If other's are actually getting more, ask yourself why, are all things equal? Do they have the same responsibility as you, same work load, same education, same personal drive, same dedication? If yes so to all those factors, then it seems you officially do have a problem, and should consider discussing your issues with your boss. A conserned boss will welcome the input.
However, if this is not a "career" job for you that you're referring to, then just seek employment elsewhere.
Of course, first get another job, "then" quit.
Good luck!