I have the same problem. It started this morning 5/21/2010.

when i open firefox , theres unknown sirens sound . it doesnt stop . how to stop it ?

Same problem. Siren carnival sound. Cannot stop it.

Got exactly the same prob.

This is driving me crazy! What the heck is this??

It just started today 5/21/2010 morning. If I use other internet browsers, there's no annoying siren sound.

I have the exact same problem as described.

I have also the same problem...

As do nI

Some add on is working with google. If you check Google.com you can play PacMan, celebrating PacMan birthday. Regardless, the sound is annoying and everywhere i go.

Nobody with a solution?

Same problem. Am running Ubuntu 10.04 with Firefox 3.6.4. Siren sound started when I opened a random window, not directly after an install or reboot.

just started at 11am 5/21/10

Methinks we've been invaded !

Is there nobody who know what this could be?, started 21/05/10, like by all the others

Just started 15 mins ago

I added the Flashblock add-on and it doesn't do it anymore when I open Firefox.

This is SOOOOOO ANNOYING. I want to pull my hair out . . . and I'm BALD!!!!

Same here. It just started about 1/2 hr ago.

The same here. Brand new mbp, got it just yesterday!