I'm seriously douhting if OPML is the right thing for the task. Uche goes one step futher and suggests XML formats for outlining are complete rubbish. Danny Ayers also gets the boot in on OPML. Honestly he has a point but offers up a couple of others which I had not looked into before. OPL in reaction to the ugliness of OPML. Looking at the spec, I'm not sure it goes quite far enough. XBEL on the other hand looks too wildly different but useful for outlining. Uche also did a follow where he reviews. I like the idea of XoXo but prefer the idea of using XHTML or RDF which is easily parsed and integreated into other processes.
Then I found Wikipad… and had high hopes for a pocketpc version like this palm version or even this mobile phone type version. Wikipad doesn't have the name of something like Voodoopad but it certainly does do a good job of notetaking for now…