I have gotten really good last minute deals in the past, but travel agents these days can't afford to shop around for you. So, I would go to the cruise lines' websites. If I find one that I like, then I call my agent.
Ken, You reminded me. A couple of years ago, I went to several cruise sites and signedup for their newsletters. So, I get a constant flow of deal to check out. So, puppy, you might want to sign up with these too. If I find time I'll put out a list, but vacationstogo is a good starting place.