An iPod edition of the ESV Bible is available for free at: http://www.podbible.org. This works for Nano, Classic and Video iPods thru the Notes application.
An iPhone or iPod Touch edition of the Bible is available for free at: http://www.touchbible.org. There are multiple versions of the Bible available thru touchbible with internet access. For the occasions when you do not have internet access, you can download and store the KJV Bible in your Touch mail application. I also recommend the site: www.biblegateway.com.