You'll need to have a livejournal or a registered Open ID (http://openid.net/get-an-openid/). The latter is handy for commenting on LJ/DW in any case: it means you don't have to use the anonymous commenting feature, so you won't get confused with someone else of the same name doing so!

Go to my profile page: http://lilliburlero.livejournal.com/profile and click on 'send message' from the bar along the top.

Let me know if there are any problems.