Aranor mentions this hint off of the ChimeraChanga application's Version Trackerinformation panel. Just add the following line to your prefs.js file:
user_pref("browser.download.autoDispatch", true);Works for me, but I'm using the 11/22 nightly build. Might work for straight v0.6.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20021127053814717