can i install mountain lion that came with my new imac on my older macbook pro?

Check out KB Article: http://support.apple.com/kb/ht4854
How to install Lion or Mountain Lion on multiple computers

The answer to your question I believe is in Apple's license agreement: http://www.apple.com/legal/sla/docs/OSX1082.pdf

Huks wrote:

Thanks. I checked that but there it only told me how to do it if I bought Mountain Lion from the App Store. I didn't, it came with my new imac...

You cannot install that copy of Mountain Lion on any computer except the one it came on. The license coes not permitthat, nor will the App Store. You need to buy a personal copy to install on any other Mac that you own.

Cheers

Pete

It's $20. Buy it and it's good for up to 5 computers. Where else can you do that?

Alfred DeRose wrote:

Buy it and it's good for up to 5 computers.

No, it's good for as many Macs as you own or control.

The 5 device limit is for iTunes store purchases, not Mac App Store purchases.

Fine, even better. The point I was really trying to make though is - IT"S $20! :-)

That 5 or 10 limit keeps getting thrown around because the SLA isn't clear. Many people here come over from Windows where the software anti-piracy crap will physically limit them to a certain number of installs. Because of that, I like to correct that 5 device limit whenever I see it as it tends to cause consternation with the switchers.