Pre ai lenses damaging dslr?

Will pre ai nikon lenses (50mm series E 1.8 prime) damage the new dslrs (d5000)?

Some websites say it works fine but no metering and auto focus, and some websites say it will cause damage to the body.

what kind of damage will it do? And how does it damage it?

It should definitely not be used with a camera body that has a link to an autofocus motor, e.g. D90, D300, D7000.
According to
http://www.kenrockwell.com/...y-lens.htm
it MIGHT be okay on a body which lacks an autofocus motor, e.g. D3100, D5000.
If it resists being mounted, don't force it.
Thom Hogan has a chart with similar result:
http://www.bythom.com/lensacronyms.htm

Some of the pre-AI lens mounts go deeper into the camera body than later lenses - and when the mirror flips up to take the image, it can hit the back of the lens - this will permanently damage the mirror and wreck the camera.
This has nothing to do with the lens 'resisting' mounting and will only be evident when you trigger the shutter (ie. When it's too late).