I should begin this post by mentioning that currently SQL Server 2005 Integration Services does not support Network Load Balancing (NLB) in the traditional sense. You can't just string together a series of SSIS servers, point them at a list of jobs and expect them to chew through them dependent upon available processing time and bandwidth.
Instead Microsoft recommends a "manual procedure" to perform SSIS load balancing. I am posting this for my own reference in the future, but it might come in handy to others searching for the same information. Here is a link to the info on MSDN.