Rumours abound on the Net that Facebook, now valued at over 11 billion euro and getting closer to half a billion users,  might be joining up with Eventbrite to let users sell tickets to some 3.5 million events added to Facebook each month. This partnership could prove to be extremely lucrative as Eventbrite is already is doing over $100 million in gross ticket sales this year and with a lockdown deal in Facebook, could easily lift that up many fold. Musicians and other celebrities are tapping into the reach of Facebook - Britney Spears has a staggering 2,598,485 fans and Lady Gaga is probably the most popular singer on the social media network with a whopping 5,579,848 fans. Selling tickets for gigs via Facebook is a very viable option. And Eventbrite will likely sell between 7 and ten million tickets in 2010 even without a Facebook deal.

Earlier this month TechCrunch confirmed that Facebook was to sell tickets to its future F8 developer conference through Eventbrite... however, there was no indication that the partnership extended beyond that.

One analyst on Twitter, Nathan Wright, was warning Ticketmaster to beware:

"Eventbrite acquisition would make perfect sense - I expect Facebook to become a major ticketing engine. (Watch out Ticketmaster!)"

Then a Techcrunch reader noticed that facebook.eventbrite.com linked to a page showing the image above (the page has since been removed). The message says:

Collect money for your event with Eventbrite

Eventbrite is partnering with Facebook to enable you to collect money for your event. Your attendees pay with credit card and Eventbrite collects the money on your behalf and sends you a check when your event is over. We charge a small service fee for every ticket sold. 5.5% + $.99c, which attendees pay, costing you nothing.

Eventbrite has helped event organizers around the world sell over 10 million tickets. We’re excited to help you sell your and put some delightful cash in your pocket.

While Eventbrite previously implemented Facebook Connect in order to let those attending to publish events they have RSVPed to on the site, by all appearances, this will be a much more tighter integration. The details of the new integration have not been published, but the screenshot below, initially published on Techcrunch, makes the partnership pretty obvious.