Why does Google Chrome launch multiple instances of Google Chrome Helper?

Google Chrome Helper instances are used for various plugins you may have installed. Unless a plugin is glitchy or doesn't play nice with other plugins, there is generally no problem having some or many Chrome Helper processes running.

This Wired article explains a bit about Chrome Helper.

Google Chrome launches multiple instances on my machine here too, so I think that's normal.

If you have the beta or development version of Google Chrome, you can get the normal one here.

Note that because it is a different version it's format is different, you will have to either delete your profile and log in again, or set a different profile path.