An SDK aka Software Development Kit is basically a package that will allow users with development skills to make their own applications for a player. This is what allows people to make apps for the iPhone, for instance. With the Samsung P2 users have been wanting an SDK since the player came out, without luck. Cowon O2 users however are luckier and Cowon has released an SDK for the O2 with the player having been on the market only a few weeks.
To use the SDK the player needs to be using firmware 1.12, which is currently in beta stages. The SDK itself is available to download for free from Cowon’s site. This should certainly make the player even more sought after and we can only hope the S9 will get the same treatment once that’s out.