I don't think the corpus is available for download, but Yasumasa Someya has an online KWIC concordancer for a 1 million word business letter corpus (which I use to help prepare classes on business email writing for ESL learners)...
http://ysomeya.hp.infoseek.co.jp/
---------------------------------
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software
This archive was generated by hypermail 2b29 : Thu Jul 24 2003 - 16:24:16 MET DST