Apple’s iCloud service hasn’t even been formally introduced yet (it will be today sometime after 1PM Eastern), but it is already drawing antitrust complaints.

iCloud is expected to add a music storage element to Apple’s current digital music offerings (the largely successful iTunes), and Berlin’s Simfy, another music service, says Apple has been withholding approval of its iPad app from the App Store. According to a report from The Next Web, Simfy has filed an antitrust complaint in Germany. Simfy CEO Gerrit Schumann is quoted as saying:

“We believe there is a connection between Apple’s iCloud development and their blocking our application. As we offer a true triple play streaming service (mobile, Web, desktop) – it seems Apple is worried about competition.”

“We have always considered Apple an important partner, but it is unacceptable for Apple to be able to control the market in this way. The App Store is a key marketplace we use to reach our customers. In the meanwhile,Simfy users are rightfully complaining about the lack of this app for the iPad. Of course, we ourselves are true fans of Apple and its products. That is why it was so disappointing and incomprehensible to us that we have apparently been blocked intentionally for months now.”

Apple has allowed its app for the iPhone and iPod Touch in the App Store, which does make any alleged withholding of the iPad app seem somewhat questionable.

Apple, according to an investor in Simfy, has not responded to the company’s inquiries (including those from lawyers).

So far, little is actually known about iCloud, as Apple has yet to introduce it beyond an announcement that it would be discussed in today’s keynote. It wouldn’t be fair to either party to rush to any conclusions about what is going on here before we even know the full extent of iCloud’s functionality.

In terms of competition, Apple’s iCloud should be competing with a lot more players than just Simfy. This includes recently unveiled offerings from major web companies Google and Amazon, not to mention whatever Facebook has up its sleeve.

In addition to iCloud, Apple will also discuss new versions of its iOS and Mac OS X operating systems today.