How do I make firefox automatically open downloaded files rather than save them?

Automatically opening files you download from the web is potentially very dangerous which is possibly why there isn’t an option for it. I’m not on a terminal with FF3 but I’ll check what my options look like when I get to one and see if I’m able to do it to be sure.

I just spent about 15 minutes digging through about:config and I couldn’t find anything.

I’m not sure I can help, or explain it well, but I will try.
Go to Tools
options
applications
You see the list of applications? Those are the ones from earlier FF where you were asked what action you wanted, you said save, it asked always, and you must have said yes.

So what you want to do is ‘change’ the way FF3 downloads…so…
Fine a file type in the list that you want to change where it downloads to…

Say you have an Adobe File in the left column, highlight it, then go to the right of it and a drop down menu will open. You should get an ‘always ask’ place to dot-in. From there foreward FF3 will always ask you what you want to do with these types of files.

If there are many many files, you could delete them all and start over…you’ll then be prompted each time….

Let me know if I’ve made sense.
Namaste’

Ehm, it’s not that difficult, if I understood you right…

Go to Edit->Preferences (or Tools->Options if it’s the Windows version), then under the Main tab (the default) there’s a heading Downloads where you can choose between “Save file to (...)” or “Always ask me where to save files” – the latter being the one you want, so you can select “Open with…” if you trust the file.

yes, it may just be for THAT particular file type….but you can change it one by one for all…give it a try and let me know if it works for you….