Two quick ways to help resolve your problem : Requires Android 2.2+ : Move all

Two quick ways to help resolve your problem: Requires Android 2.2+: Move all apps to the SD card that will let you do so. This will trim down how much space these apps use in your internal memory and moves some of it to the SD card. However, remember that these apps will not instantly show up on start up or if you mount the SD card for any reason. Use an app like SDMove to figure out which apps you can move that you haven't already moved. SDWatch will alert you in the future if an app you installed can be moved to the SD Card. Delete applications that you are no longer using. If you haven't used it in weeks, remove it. Every couple of weeks, take a glance at all of your applications and see which ones you aren't using and remove them. You can filter applications by their size in the settings to quickly remove the bigger sized apps first. Also remove anything under Settings > Applications > Running services that you aren't using, such as extra keyboards or other notification services.