Hello and welcome to Android Forums, mjg060468.
Are you using the stock keyboard or an app downloaded from Android Market?
I'd first go into the application manager and see if whichever keyboard you've got missing is listed there: menu > settings > applications > manage applications.
If so, clear cache and data then reboot your device.
If it's the stock keyboard that is missing, a reboot might remedy that. If it's a Market app, just uninstall then reinstall it.