In the statement Serbia issued "annulling" Kosovo's independence, they refer to the UN Security Council Resolution 1244 of 1999. This Resolution ended the war in Kosovo and created the temporary UN administration. The document contains a passage that states support for the "sovereignty and territorial integrity of the Federal Republic of Yugoslavia". While this is all well and good, it appears that any sovereignty Serbia has had over the last nine years has been zero and virtually symbolic in nature. As for their territorial integrity, Serbia lost the right to govern Kosovo due to the conduct of the Milošević government in revoking Kosovo's autonomy in 1989 and the nasty decade of direct rule Serbia brought on until the 1999 war.
Russia claims that Kosovo independence will give every other area a reason to secede. However, this falls flat in my mind. As stated above, its obvious Kosovo is a different case for the reasons set above. There is also another reason this is special. Kosovo's independence is another chapter in the breakup of Yugoslavia that started with Slovenia, then Croatia, Bosnia and Herzegovina, The Former Yugoslav Republic of Macedonia, Montenegro, and now Kosovo. If Yugoslavia was still one nation and Kosovo declared independence, I would understand Russia's position here. In this case, I can't.
As for me personally, I'm happy Kosovo is free. The people wanted it and for me this is the number one reason to support their recent action. However my happiness is muted by the lack of agreement on ether side. In any case, that's ancient history now. Let's help Kosovo in going the right way.
It will be hard, but we can do it.