Is there any mod for placing some text/ picture on the rocket?

[muzzdiez]

As far as I know, KSP does allow to place only flag on a side of some parts.

And what I have to do, if I wish to "name" a rocket on its side (as in the "Proton-M" russian rockets), or just write something like "USA" word as on the first stage of Saturn IV, or something else like this?

Well, I accept both ways: requested word may be a picture (e.g. previously prepared .png of .gif with transparency), or it may be written in-game with some kind of addon or anything else, using any installed font and colour.

Google does not help in any cases of requests as "ksp text on rocket", "ksp write on rocket", "ksp picture overlay", etc.

[Kowal04]

Maybe this one http://kerbal.curseforge.com/ksp-mods/222813-flag-decals-v2-1

However, I don't know if this work in 0.90.