The Russian spindle is a support spindle, singles are spun similarly to the techniques used with a tahkli spindle. The traditional fiber is Orenburg goat down, though in the US, they are typically used for Cashmere, Yak, Bison, and similar short stapled, fine fibers. The cop of handspun is built up on the lower end of the long part of the bulb.
The picture above shows traditional plain Russian spindles, the one with fiber is very full!
I find it easiest to spin this wooden support spindle in a ceramic dish for minimum friction.
Plying is where the fun of Russian spindles come in, as to ply, you first take a full spindle of singles and silk thread (traditionally, though you can use what you want!) and wind it onto another Russian spindle. Yes, wind two strands together, maintaining even tension, without plying, onto the spindle!
(this photos shows artsy-yet-functional Russian spindles, by Tom Forrester)
Then, you spin counter-clockwise and lift the end off the spindle as twist enters the yarn that is being released from the spindle. Cool, no? You take that new length of plied yarn and wrap it around a "Russian plying disc", which is simply a 2-inch diameter circle of lightweight cardboard (think cereal box or the cardboard that is inside flat-packed panty hose). Then, holding the disc, you repeat this process for a new length, wind it on, and continue.
The yarn is set by steaming it on the disk, or simply mist it and leave it to dry if your environment supports that.
The spindlitis list on YahooGroups has been having a Russian Spindle challenge, uploading to YouTube some lovely videos, especially Faina's, on Russian spindling.
And then I found this variant, of Tibetan spindling:
How cool is that!
As far as instruction goes, Connie Delaney has a pamphlet on Russian Spindling, Ghalena Kaleva's book Gossamer Webs has a segment on Russian Spindling, and the Spin-Off Handspindle Treasury has a piece on these spindles as well. The video Spindles Around the World by Barbara Clorite-Ventura shows these spindles in action.
Tom Forrester's Russian Spindles are available at The Bellwether, as are ceramic bowls.