I had already started, but as I predicted, it's hard to keep typing all those Dilbert Transcripts. But today I found that someone else is also busy, see the website and the web-app where you can help. The resulting website isn't indexed by Google, so not searchable (yet). See if you can help !
Using some of the texts, I found two other list with all of these texts, but it's arranged by book: here and here. I'm going to use these two to fill my own text-search index. I already borrowed a part of it, used a perl-script to generate some description files, and add text to the already existing files. I'm re-indexing the Dilberts now, so I can test the results. As more people are doing this, and the official website isn't doing this, perhaps it will sometime be available on the internet.
update: I now have a description for all Dilbert's I have, but I still have to check and edit all the contents.