I've gotten into this once before (here) and when I speak of "Russian" involvement, I mean Russia as a political entity.
It's better to say "Yeltsin administration", just to make it clear, or even better "the pro-Clinton Yeltsin administration". I hate it when people interchange Soviet Union for Russia and when we're talking Yeltsin's foreign policy, that's almost the same as the USSR. Russia was on Greece's side during WWI, but the Soviet Union supported Attaturk. Go figure...
No doubt, Russian individuals supported Serbia (and still do).  Absolutely true that some Russians came to fight also.  However, without the force of the big Russian bear behind them, Russians, like Serbs were just canon fodder for Nato bombs.
You can be sure that if there was a land invasion there would be many more Russians there, which is why some of Yeltsin's people were desparately trying to pass legislation that would help prosecute Russian volunteers. When you're being bombed from 10,000-20,000 feet there's not much a soldier can do even with an anti-aircraft weapon.
 I think most Serbs, prayed that Russia (under Yeltsin) tried to help Serbs, he did not.
I think that their prayers were being answered, because if the Russian people hadn't responded to the bombing the way they did, the Yeltsin government would have done far worse.
Btw, I absolutely LOVE Greeks for the record and I do highly respect their response during the bombing.
Where you and I differ is our view on Putin.  While agree he is better than Yeltsin (isn't anyone), I don't see him going to war over Serbia.  We have to be realistic about it, in assessing the overall importance of Serbia in world politics.  Do you really think Russia is anxious to put her troops in harms way to help Serbs?  Why would they be?  I just don't think any Russian leader (save maybe some of the more radical opposition) cares enough about Serbia to really get involved.
I think Putin as an Orthodox Christian really does care. He's just not as openly verbose about it as some of Russia's other politicians are.
Someone like Zhirinovski will wave his fists and say that NATO will be destroyed, but ultimately he doesn't have any effective manner of doing that, nor do I think he really cares deep inside about anything other than getting the votes from his electorate. The communist party will also stammer up and down about the Serbian issue, but only because they hate the west period, and because they are using the patriotic sentiments of the older generation to win support. The communists were hoping to impeach Yeltsin during the bombing, Zuganov was aiming to jump into the president's chair and he knew that standing behind the Serbian issue was the best way to win popular support. Thank God that didn't work, it would have been worse for both Russia and Serbia.
I think that if anything happens with the Serbian issue we'll see Putin playing a major role on Serbia's behalf - as much as any political figure is willing to take a risk.
But for Putin to simply walk out and say "If you touch Kosovo we're going to immediately force march our troops through NATO member Romania and send our aircraft" is suicidal. That's identical to declaring war on NATO. NATO is then in a great position to send aid to the Chechens, they'll press on all their levers in the Ukraine, they'll immediately make some very lucrative overtures to starving Voronin in Moldova, they'll get their ally Latvia to up the pressure against the Russian minority living there, Poland will get a chance to show its NATO loyalty again, China which is chopping away at Siberia will get more license to do whatever it wants, and it will turn into a war for the dismemberment of Russia (which has already begun). They'll also strangle Russia with embargos. Russia's more moderate Islamic community will also be more prone to extremist propaganda if this happens.
If anything the strategy will be to properly convince NATO that defending the Albanians is not in their interest, that the Serbs aren't going to give up and there will be others that will help the Serbs if the west thinks it can bully away Kosovo.
I'm sure that if the military situation escalates we'll see a drift of Russian volunteers as well as others, which is what happened during the Balkan wars two centuries ago. There are many ways of fighting the war without sending aircraft carriers and tanks. Let's just pray that it doesn't get to that and that the NATO leaders see beyond their ego.