The Ovi Store has opened for business. Nokia (NYSE: NOK) today officially launched its mobile content and application store, which some analysts are calling the Finnish handset giant’s “last castle”, as it tries to shore up slowing handset revenues with services sales.

UPDATE: Tricia adds:  Nokia said today on its Ovi blog that shortly after launching the Ovi Store at 2 am ET, they began experiencing “extraordinarily high spikes of traffic that resulted in some performance issues for users accessing store.ovi.com and store.ovi.mobi.” Nokia said they began to add additional servers to fix the problem, but that also caused in intermittent performance improvements. For those who were accessing the store through the downloadable client, “there were no reported issues.” Nokia said: “We apologize for any inconvenience this may have caused Ovi Store users and encourage you to continue giving us feedback as we develop the service further.”

The failures led TechCrunch to call the launch “an utter disaster.” It also pointed to some flaws, such as applications appearing and then disappearing. The All About Symbian blog was also critical, mentioning slow wait times while pages loaded, and the fact that it took three clicks to buy an application. In a brief trial on the 5800 XpressMusic, I found the web site was fairly fast. It took some time to figure out that the store had to be downloaded from the Menu screen on the device, rather than the website, like the BlackBerry App World. Once downloaded, the experience was improved compared to the mobile internet version. Likewise, it was very easy to look for apps on my computer, and send them to the phone via text message—although you had to wait 30 seconds between apps. Clearly, with a worldwide roll-out of this magnitude, there will be hiccups, but nothing at this point seems like a total failure—just a work in progress.

The store is available to what the company estimates is a global audience of 50 million Nokia device owners across more than 50 of its various handset models through store.ovi.com on mobile browsers, or as a downloadable application. Customers in eight countries, including Australia, Germany, Ireland, Italy, Russia, Singapore, Spain and the United Kingdom, will be able to pay for their apps directly on their mobile phone bill. As emerged earlier, there will be no carrier billing in the US. To counter this blow, Nokia also announced that AT&T (NYSE: T) plans to make the Ovi Store available to its customers later this year. No word on the particulars of this specific deal, but given how hard Nokia has tried to court the US carriers, it will be interesting to see what AT&T was able to extract from it.

Analysts, meanwhile, are skeptical that the much-awaited Ovi Store can match the runaway success of Apple’s App Store, which recently clocked up its one-billionth app downloaded less than a year after its launch. Global Crown analyst Tero Kuittinen told Reuters that the Ovi Store was “in some ways the last castle for Nokia” in which the handset giant “tries to re-group and muster its forces for a counter-offensive.” He noted that Nokia past attempts to offer mobile content haven’t been particularly successful and called its gaming service N-Gage and its unlimited music offering, Comes With Music, “industry laughing stocks.”

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