Silk top is a lovely fiber to spin. That said, it can be a challenge to the new spinner, since it is very slippery compared to wool. Wool fibers have scales on them, which help them hang together. Silk has no scales, it is very fine and smooth. That is also why it is so shiny -- light bounces off of its smooth surface.
Silk also has a fairly long staple length -- so if you have been spinning fine wools with short staples, you will find you need to keep your hands further apart to draft easily when spinning silk. Keep your hands at least 6-9 inches apart so that the silk fibers can draft -- you want your hands further apart than the staple length of the silk fibers so you aren't tugging both ends of a fiber when you draft in a one-spinner tug of war.
When spinning silk, you will find it needs alot of twist to hang together ... my "test" for alot of twist is to let it twist back on itself (the ply-back test described here) and see that there's no open loop at the bottom of the ply-back length. Because of this, silk is typically spun fairly fine -- from fingering to laceweight (14 - 20 wraps per inch or more).
And make sure your hands are smooth -- silk (unspun) snags on everything. I find, if I've been gardening or doing outdoor work in general, that a nice dose of hand lotion smooths out any rough edges before I tackle the silk.
Usually I'll spin silk either with a very fast spindle such as the Natalie or another that has weight near the shaft rather than out at the rim; it's the one time when I'm going for spindle speed over spindle spin-time. I find putting twist into the silk quickly ensure it will hang together while I'm drafting more.
On a wheel, I'll spin at a high ratio, and try to minimize draw-in by reducing the scotch tension or tension on a double-drive band until I have complete control over whether the fiber is drawn in or not. On a Louet wheel, or any other wheel with hooks on the same side of the flyer, you can thread your yarn back and forth on that side from hook to hook across the bobbin to further reduce the drawn-in.
Silk is also typically finely spun. For more on fine spinning, see the earlier entry, How can I spin fine yarn? especially the notes on handling plying with finely spun singles.
(shamless plug: The Bellwether has lovely handpainted Tussah silk, a wonderful Tussah/Rayon blend, and Natalie spindles, as well as lovely Bosworths, Forresters, and other spindles that would enjoy helping you spin silk, along with Ruth MacGregor's book, How to Spin Silk on a Top Whorl Spindle)
Happy spinning! If you've learned something you'd like to share about spinning silk, or have questions about spinning silk please email me or add a comment here.