Reading Lists can be made via RSS Readers, RSS Re-mixers (Newsmastering), Social bookmarks services, OPML editors…that’s all I know of so far.
Create Reading Lists
BlogBridge…as mentioned you can also use (subscribe) to Reading Lists in BlogBridge.
Bloglines…when you export your subscriptions it is done via an OPML URL (this makes it dynamic…other RSS Readers will export OPML only to a local file, it needs its own unique URL to be a dynamic Reading List)
I’d like to see Technorati Favourites have an OPML URL (Reading List) by default…maybe soon, as Blog Finder groups have OPML’s.
I’d like to see these tools be able to not just create, but also use Reading Lists, just like BlogBridge.
Use Reading Lists
Many services allow the export/import of OPML files/URL’s (batch loading feeds), but not many allow you to subscribe to the OPML URL itself (instead of the feeds), so the changes in that OPML URL automagically reflect in your rendition.
[ADDED 28/02/06: OPML Browser is now called Optimal…it reads RSS feed content, and also opens OPML inclusions within the same page as an outline]