We came across a very simple problem, and solution is more simpler. :)
We wanted to change the message appearing when there is no document in the document library.
Solution:The text comes from the core.resx resource file, located in 12\RESOURCES. It's divided up into four resources; just open the resource file in any text editor and search for "noitemsinview_doclibrary", and you'll find the strings.
NOTE: This will change globallly... and you shouldn't rely on changes to the system resource files directly - hotfixes or service packs might overwrite your changes.