I recently setup a 3 tier farm with a wfe an app server and sql server. When creating the apps in central admin i didn't notice the app url was the app server and not the web front end, how do i fix this?
When you created the web application, be default all the url points to the APp server.
You have to make the changes in the Alternate Access Mapping,
From Central admin > Application Management > Configure alternate access mappings
From this page the select the Web Application from Right dropdown select the web application. now you can edit the URL here.
After that make sure IIS settings are correct on WFE, for the web application(proper port number bind it)...all the time its correct but just for making sure.
Also if their is any web.config changes or any customization make sure applied to the WFE.