Wood of course dries faster in smaller pieces. I would advise roughing out any slabs or bowl blanks that you want sooner rather than later. It may seem wasteful, but cut the heart of the wood out now. This will split the most and split soonest, and the cracks will spread to good wood that may not have split otherwise. Or, leave it and enjoy some fun and beautiful inlay work later!
The wood will shrink and warp a bit as it dries, so cut your slabs slightly thicker than you need them. A good way to go is to take a log and cut a slab right down the middle that is about 20% of the log's overall thickness. The ratio doesn't need to be exact. This leaves one slab with the heart in the middle, and two pieces with a taco shaped cross section. Cut the heart out of the slab, which leaves you with two smaller slabs each with bark on one side. These are great for spindles or pen blanks. The other two pieces can be sawn into bowl blanks, more pen blanks, or anything else you might think of.
Seal the end grain and the surrounding 1" or so to prevent splitting. Anchorseal works great, as does dipping them in paraffin or painting them with a few coats of latex paint. You can pack your slabs/blanks in the green wood shavings that you just made and roll them up in a paper grocery bag to help smooth out the drying process, but it probably isn't necessary at this point.
Obviously, wood-eating critters are likely to be living in this wood. Keep that in mind when storing it!
