anyone know?

I don't think it's illegal anywhere.

It's just looked down on by ISP's.

It's definitely illegal in most places, though I'm not sure of Russian law. The first D in ddos stands for distributed, and you can't have a distributed attack without infecting a bunch of computers. Remember the conflickr worm and the large amount of prize money Microsoft was willing to give to the security expert who could take it offline?

I believe it becomes illegal if you cause over X amount of money in damage when doing it.

Otherwise it is generally ignored.