i post my events to:upcoming, going, squidlist, sonicliving, sfstation, yelp, clubzone, socializr, thrillist.com, eventful.com, sf.funcheap.com, zvents, x-treme guide, napkinnights, nitevibe, topix.com, onlyinsanfrancisco.com, linkedin, facebook, flavorpill, experiences.noo.comdaily: squid, yelp, socializr
Yes, all are manual.
You might want to add Identica to your list. It's essentially an open-source, open-standards, more reliable version of Twitter, but it supports OpenID (so you can use your existing LJ account) and identi.ca updates can be syndicated all over the place (eg. Identica->Facebook,Identica->Twitter).
No, the increased reliability is thanks to federation. Instead of a single point of failwhalure like Twitter, anybody can put up an instance, and you can subscribe to others' updates across servers. Think e-mail: instead of everybody using AOL, you can take your pick of provider and still send messages to anybody in the network. This is the reason it's taken off, with >1 million dents sent in the last three months on the "main" identi.ca site alone, and the open-everything approach is just a bonus.
I don't buy that for a second. I believe the only reason Jabber works for large numbers of users is because of the few servers subsidized by the deep pockets and staggering bandwidth of the likes of Google and Livejournal.
But, whatever. It doesn't matter, because Identica (and, for that matter, Twitter) don't really do anything that is useful to me in terms of promoting events.
It may not work well for your purposes, but ArtistData (http://www.artistdata.com) tries to make updating all those sites a bit easier.