Go to any of the major websites (Travelocity, expedia, orbitz) or any of the large cruise dealers (vacationstogo, cruise411, cruise.com etc.) and look for a cruise that appeals to you. When you find something interesting, go to
www.cruisecompete.com and let lots of agents compete for your business.
You'll find great information at a site that I use and contribute to a lot -
www.cruisecritic.com
We're doing our first Alaska cruise next September. A bit late in the Alaska cruise season, but a great itinerary - Vancouver - Alaska - San Francisco. We'll be on Celebrity's Infinity as we like Celebrity a lot

(We're doing a transatlantic from Ft. Lauderdale to Southampton on Celebrity's Millennium in March).
P.S. She
just got back from an Alaska cruise -- in December??