To get the relevant data files:

http://www.megaupload.com/?d=Q9PPTANA for the program CDS Explorer
http://www.slightlymagic.net/software/mws/5-mtg-masterbase for card data
http://mws.mtgbr.com/index-us.html for latest card data (masterbase)

You can use the same site for card data and images.
Nevertheless, you may find it more convenient to use this torrent:
http://www.slightlymagic.net/forum/viewtopic.php?f=15&t=445

CDS Explorer only runs on Windows and I have only tested in on XP.

You will need to open the extracted masterbase and sets files in CDS Explorer,
select all rows and export them to Excel documents.
OpenOffice's Calc can take that, ensure that Unicode gets handled properly,
and then save-as CSV files for consumption by MTG.

You may adjust the paths in src/data.lisp's top defvars or rename and place
the files as instructed below:

The resulting csv files should be named magicdb.csv and sets.csv and be
placed under Data/ in the mtg root directory.
The card images will likewise need to be extracted.
Maintain the existing directory structure and place "Fulls" under Data/
in the mtg root directory. Only Full images are supported at this time.