I'm thinking about looking around for another job, but I don't know when I should tell my boss because I would like to see what kind of opportunities I can land before I even mention it. The reason I'm reluctant to tell him right away is I'm afraid he'll begin the process of replacing me. If I don't tell him while I'm looking around, then I can't use him as a reference and he'd most likely give a great recommendation. If I were to leave and go work for someone else, it wouldn't be until after I finish my current project which ends in two months because I don't want to screw anyone over.

How would you approach him about this and when?

Thanks in advance for your wisdom!