It's the nature of a post to check or crack
The way the post is cut from the center of the log usually results in cracks like you are showing.
Rather than "repairing" the crack, which in my opinion, won't last I would conceal the cracks with white 30 yr exterior caulking from the Home depot. It's somewhat flexible, waterproof and will last quite a long while. The cracks I see are not structural and will not affect the strength of the post. Just fill them up and they'll be fine. Something like this: http://www.amazon.com/27062-Butyl-Flex-Gutter-Flashing-Caulk/dp/B000DZBFRE%3FSubscriptionId%3D13J52J68PEMPA77VHSR2%26tag%3Dpctiwo-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D165953%26creativeASIN%3DB000DZBFRE
The answer to your question will only be as detailed and specific as the question is detailed and specfic. Good questions also include a sketch or a photo
Last edited by woodnthings; 07-22-2011 at 06:19 PM.