BrickStore is a BrickLink offline tool. It is multi-platform (Windows, Mac OS X and Unix), multilingual (currently english, german, french and dutch), fast and stable.
Browse and search the BrickLink catalog.
Easily create XML files for Mass-Upload and Mass-Update either by parting out sets or by adding individual parts (or both).
Download and view any order by order number.
Download and view your whole store inventory. An easy way to use this for repricing, is to use the BrickLink Mass-Upload functionality.
Easily create and upload Wanted-Lists (this is not 100% complete yet - see below ).
Price your items based on the latest price guide information.
Create XML data for the BrickLink inventory upload.
If you load files which contain items with obsolete item ids you can fix them using the BrickLink catalog change-log (this could be automated with some support from BrickLink).
Calculate differences between two documents: you can easily check, if it is possible to build a set given your current inventory.