I've never heard anything about XPCOM being deprecated.
I hope it's not -- the project I'm working on at TomTom (the TomTom Home desktop app based on xulrunner) uses XPCOM extensively.
I asked about it on the #tamarin irc chat.
It sounds like XPCOM is here to stay (although it may evolve), and it will be a while (mid-2009) until Tamarin ships to end users.
<xardox> hi! I have a question about tamarin and xpcom: are they being integrated or is xpcom going away?
<xardox> Somebody on the Lua list mentioned that "xpcom is depricated and tamarin is the future language neutral virtual machine" or something to that effect. I'm shocked to hear that xpcom is depricated.
<xardox> So I'm wondering where he got that idea from...
<Waldo> xpcom is unlikely to completely go away for Mozilla 2; it will probably change a bit, but I don't think we can get rid of it that easily
<Waldo> bsmedberg has been talking about replacing XPCOM with a Tamarin-style ABI, but I doubt it'll happen, as does brendan
<Waldo> probably someone parroting him
<xardox> parrot -- ha ha ha! as in parrot vm. you are funny!
<xardox> parrot is a parody.
<xardox> so will there be something like xpconnect for tamarin, so it will just work with all the xpcom apis just like spidermonkey?
<xardox> we are investing heavily in xpcom and it would suck for it to go away...
<Waldo> dunno; in any case, this is the Firefox 4 time-frame, after Firefox 3 (late this year, early-ish next) and a probable 3.5 (sometime after that), so you're looking at mid-2009 at the earliest in releases for end-users
<Waldo> also keep in mind nobody's more invested in XPCOM than Mozilla, so whatever is done has to be something we can handle :-)
<Waldo> and by the way, the parrot thing was an awesomely bad joke
<xardox> you mean I made a bad joke, or the entire idea behind parrot (and its announcement on april fool's day, and the fact that so many people too it soooo seriously) is a bad joke? :)
<xardox> Lua hackers would love to integrate the Lua VM with the browser, and I suggested looking at the way pyxpcom works, and integrating it the same way mark hammond integrated Python, since the browser has been worked over to be more language-neutral to support that work.
<xardox> ideally all the happy vms will play together nicely via xpcom.