So why are we holding our MobileBeat conference tomorrow?

Focused on investors and entrepreneurs (developers), we’re asking the big question: Is now the time to go mobile? And if the answer is yes, what do you have to keep in mind?

As part of the answer, we should take a look at which companies have succeeded so far. What are the biggest hits, from an investor’s perspective?

The answer: Over the past decade, most money has been made on investments in companies building the back-end infrastructure of the wireless networks, but even here the returns have been mixed. An almost negligible sum, meanwhile, has been made from investing in mobile applications that run on phones. With the rise of the mobile browser (think 3G iPhone), however, and better networks to allow quick browsing, people are likely to surf the mobile web more. Open platforms are helping people find a way around the stagnant operators, too. That’s what suggests the types of success we see in the future might change.

To be sure, the iPhone 3G has raised the hype decibels — and it’s just not certain how investors will fare by investing in applications. We’ve got a venture capitalist panel starting at 11am where we’ll chew through these questions, how things like GPS are changing the game, and how apps (if they can become platforms) may become huge hits. We’ve got leading investors, such as Rick Segal from the Blackberry Partners Fund, Richard Wong, from Accel, Shawn Carolan, of Menlo Ventures — and even Rupert Young, of AT&T, who says the company has made few acquisitions so far, but that’s about to change.

So, beyond the iPhone 3G hype, where has the cold hard cash been made?

First, we looked at the top 10 IPOs from 2000-2008 (source: VentureOne). The reality: Only 10 companies went public. Industry watchers will also note that Vonage Telecommunications, one of the companies on the list, had a disastrous enough IPO that shareholders revolted with a class action lawsuit.

Notably, half of the 10 did their IPOs in early 2000 during the interent boom. After a nearly four-year nuclear winter, Atheros Communications got through the gates and raised $126MM in 2004 with its IPO. Only four of the 10 had billion dollar values at time of going public.

There are few household names on this list, unless of course you’re a fan of the cheesy MetroPCS and Vonage commercials.

A more diverse and interesting picture emerges once we focus on the top acquisitions in the 2000-2008 period (source: VentureOne). While no wireless communications equipment company had IPOs, almost half the acquisition dollars were spent on such equipment manufacturers. Navini Networks, a wireless broadband manufacturer is one example; it was sold to Cisco Systems for $330 million dollars in December 2007.

The most eye-opening trend is the emergence of Nokia as the biggest investor over the last 18 months. The phone giant has bought Trolltech, Navteq and Enpocket. Missing from the list (I don’t know why), are Nokia’s recent acquisition of Plazes, a location technology company, operating system platform, Symbian, this year, and Germany’s Gate5, in 2006.

We’ve pasted the entire list of acquisitions below (provided by Thomson and the National Venture Capital Association). Note how only one company reached an acquisition price of $500 million: Danger, bought by Microsoft in April. Danger is an example of the “device-platform” trend we referred to earlier this week. Apple and RIM have shown how much value