On my vBulletin forums, I changed the template for showing forums and threads. I removed my forum title from the page title. I am simply wondering, since tons of these pages already have been spidered and indexed, will Google ever notice that I changed my page titles?
Google revisits your pages at regular intervals. For popular (high PR) sites this can be daily or for static sites with lower PR this can be monthly. Try submitting a site map to google as this sometimes helps them spider quicker.