Historically, I’ve kept my feeds in Apple’s Mail.app. However, I’ve recently found myself wanting to catch up on RSS when I’m in the car or at the gym. I needed a way to move from Mail to Google Reader.

The trouble is, Apple doesn’t have a way for you to export your RSS links our of Mail (as text or OPML). Thus, I turned to the Google, and found a fairly simple solution:

1. Export the RSS feeds as URL links in plain text (Mac OSX Leopard-only). This bash link places the export on your desktop.
   

   IFS=$'\n';for i in $(find ~/Library/Mail/RSS/ -name "Info.plist");

   do grep "http://" $i | sed "s/.*\(http[^<]*\).*/\1/" >> ~/Desktop/Mail\ Feeds.txt;done

2. Convert to from Plain Text to OPML. I used the excellent converter at http://unold.dk/code/opmlgen/ (Dead-link, update thanks to commenter Tom: http://reader.feedshow.com/goodies/opml/OPMLBuilder-create-opml-from-rss-list.php)
3. Import into GoogleReader!

Simple. I know have all my feeds in GoogleReader, and can access them whereever I am.