I always used "Send to KGTD Advanced" http://inik.net/node/48 with kGTD. It worked great, and I could choose to launch it from Quicksilver, Launchbar, Fastscripts, or just about anything else that could launch a script. It has a similar syntax for task entry as the Send to OF Script. It also has Growl notification built in, and it is GPL'ed. I haven't had a chance to hack it to work with OF, but with some careful editing, it should work just fine.