As long as it's a 2.5" SATA HDD it'll work in your MacBook..
You may wanna pick up a hard drive enclosure as well.. or one of those static-free bags that new computer parts usually come in to store your old drive.
And I assume you wanna keep all your current settings instead of having a new install?
If yes, then follow everything here, if you don't already have a time machine backup.
If not, then just get your OS X install discs ready.
If you picked up a enclosure than put your new drive in it first and connect to your MB
Use Superduper and clone your existing hard drive to your new one.
You can download Superduper and back up and clone your drives for free...
Then you just need to swap out the old drive for your new drive and put your old one in the enclosure where you can do whatever with it.
When you start up your MB with the new drive it's like nothing happened, your apps and settings will be as they were before the swap, you'll just have more space now..
You may also want to run disk utility and repair disk permissions after since it is a new drive and all..