The way that the internet is connected the same tools and resources that you would
use to search for someone in one state are the same that you would use in another. If you want to locate a person in Idaho you have the same options as the rest of the country I suppose assuming that you want to use the net for your search.
If you are not limiting yourself to the use of the internet then you will be able to get information by visiting the local relevant offices based on the information that you have and the person that you are looking for. Here you can make use of a wide range of sources such as the local courts, registrar of records i.e. births, marriage, drivers' license and so on.
If you want to locate a person in Idaho you can always pull the telephone directory and look for the person you seek there. You can consult the white pages and you will be able to conduct a search by state for whatever type of search you want to do
In some cases you might not even have to through all these things. A simple Google search could just do the trick. If not then you can move on to the other mentioned ideas.
One popular search that you can use is the government records search. You can also use the same records to find someone free in Idaho. Like the white pages home page, the government records will have different search categories that you can pick from. In this case you would have the search by records option.
The more info you have the simpler the search will be as there are a lot of records that you can browse throughCheck out ehow.com if the above mentioned ideas don't help.