How do I access bank one sensor two?? or bank two sensor one??

Here's some help on the p0151 code: http://repairpal.com/obd-ii-code-p0151 If you are going to attempt to replace sensors and need access to them, you should invest in a repair manual to help you through these procedures. AllData and Mitchell1 both have good online solutions that are pretty cheap. Here's a link to the Mitchell1 version: http://bit.ly/mitchell_repair_manuals_online