Traditionally, or pedantically-speaking, the Title field should be used for this purpose and there are certainly people who use it in this way, using tools like my Search Replace Transfer plug-in to copy the filename to the title. In practice, most people want the title to be the title, so you could use SRT to add the filename as a suffix to the title. If you want to copy the filename to the keywords, you would need some kind of plug-in or script. SRT doesn't copy to keywords because hierarchical keywords make coding more complex (eg which parent should the keyword go under?) and I've had no demand to automate cluttering up keywords with filenames.
Have you looked to see if Jeffrey Friedl's Flickr plug-in can add keywords as part of the export process? That would keep your catalogue cleaner.