Les Hill has sent me some code that solves this problem for an OPML browser written with Java that uses JDOM. I'll be posting more on it soon when I have time to try it out. He says that to read OPML, it "basically replaces the SAX parser with an almost identical parser that will recognize the XHTML entity set." Ouch.
Any thought to also handling bookmarks from Opera - don't know if the format is open. Also, do you know of the 'OPML & XSLT' tool for viewing OPML Outlines? any chance of getting it to create - de nova - an OPML document?
thx for working on OPML