There is way in Blender to sync to PCs. http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Performance/Netrender
or as Rahmound said: set an start- and endframe for Blender to render, so you can split the work to do on two PCs. Although I would recomend to render in single images (.png for example). So if one is faster, you can just give him another part to render. Afterwards the single images are easily put together in Blender or any Videoeditor. And if one picture has a mistake you can easily render it again.