Can you allow free apps to be installed without needing password on iPad/iPod

AFAIK this is an Apple restriction with any public apps.

If you develope your own you can deploy them with no authentication.

Ben is correct. Apple's policy on this is pretty clear. Anything that comes from the App Store requires an Apple ID authentication to get installed, free, paid for, whatever. Even with the "push" process allowed now with iOS5 it still will prompt the user to enter their ID (or some ID)
I think the thinking here is, Apple does not want apps pushed to users surreptitiously, probably for security reasons but also because Apple still strongly views iOS devices as 'self managed', not controlled by the enterprise. Despite this, iOS devices are making inroads into the enterprise in droves. The hope is Apple will eventually allow more control over how this all functions, but for now, their focus is firmly in the perspective of the consumer.

As Ben also noted, in-house developed apps that don't come from the App Store are exempt from this restriction. But that is the only case I know of.

I know this is an old thread, but has anything changed now with IOs8 and JSS 9.6?

Can apps be installed onto managed devices via Self Service without the need for the user to enter a password?

This process works unless the device already has a MDM managed configuration profile installed, unless there is a particular restriction that needs to be unchecked that I have yet to discover - I've already tried most of them....