if you have DBMail and an operator setup, then it's simple since 1105 is a logged error:

USE MSDB

EXEC sp_add_alert @name = 'Error 1105: Filegroup Full', @message_id=1105, @Severity=0, @enabled=1, @delay_between_responses=900, @include_event_description_in=1

EXEC sp_add_notification @alert_name = 'Error 1105: Filegroup Full', @operator_name='youroperatorname', @notification_method = 1

you'll get an e-mail like this:

DATE/TIME:3/12/2013 2:43:26 PM

DESCRIPTION:Could not allocate space for object 'dbo.bogus' in database 'trying' because the 'PRIMARY' filegroup is full. Create disk space by deleting unneeded files, dropping objects in the filegroup, adding additional files to the filegroup, or setting autogrowth on for existing files in the filegroup.