The following answer remains intact for historical purposes.
It depends on the felony. Under Idaho law, anyone convicted of any of 36 felonies may not own, use or carry a firearm, which the law defines as "any weapon from which a shot, projectile or other object may be discharged by force of combustion, explosive, gas and/or mechanical means, whether operable or inoperable." This includes firearmes, muzzleloaders and archery equipment. The right can under some circumstances be restored, unless the crime was murder in the first or second degree, or if conviction included the use of a firearm in the commission of any the listed felonies. (For a list of felonies see Idaho Code Title 18, Chapter 3, section 18-310.)
A person convicted of a felony in another state comparable to any crime enumerated in Idaho Code Section 18-310 (2) may not possess a firearm, muzzleloader or archery equipment unless the felony conviction has been expunged or pardoned by the jurisdiction of the conviction.