Importing photos into iPhoto from another computer's iPhoto library

I carry a PowerBook on trips and load my photos from the camera every day. I add labels, keywords, etc. and edit the pictures (crop, adjust exposure, straighten, etc.). When I get home, I would like to import these photos (with descriptive info, keywords, edits, etc.) -- both the original and edited versions -- into my Tower's iPhoto library. On a typical trip, I would have at least 5 gigabytes of pictures.

This seems like a task many users would want to do, but I can't find a simple method in the help file or on this forum. Any help much appreciated.