I was just wondering how to make the spawn point/zone smaller in minecraft multiplayer. I would like to make a spawn house but it looks just ugly if it's so big.
In single player, you always spawn on the exact same block (excepting beds), so I assume you're asking about multiplayer.
Vanilla Minecraft server has no way to configure the spawn area, so you'll need a server mod of some kind. (Fortunately, such a mod would be server-only; you wouldn't need to require your players to install the mod as well.) However, several Google searches didn't turn up an existing mod, so one may need to be created.
If you can't find one, try requesting it on the Bukkit plugin request forum.
I'm pretty sure that if you use creative mode and make yourself an op you can dig your way all the way past bedrock where it is nothing but empty space. Then you can no longer spawn in that block because there is nothing to spawn on. If you repeat this with other blocks in spawn you can "shorten" spawn.