I am writing this quick post because many people have pm'd me about the legalities of modchips in all scales, including purchase, installation, use, etc. Please be aware that all information contained here is for the U.S.A. (and more specifically CA) It may stand true elsewhere, I don't know.
Buying a mod chip: Mod chips are not SPECIFICALLY considered legal. It is just a chip with contact points that can, for all intents and purposes, be made from parts sold at a college books store for computer science majors. The physical chip is currently legal to purchase and to won. The data on the chip may or may not be illegal. That really depends on what the data is. If it is something that is owner by nintendo (or any other console maker, but this is a Wii hacks forum after all) that was modified, then yes it is illegal. This would make the chip illegal as well if it was sold preflashed. Non of this data for the current Wii modchips is illegal, because it was all developed without modifying any of Nintendo's code. Modchips for say, the XBOX1 were, for the msot part, shipped not flashed because they worked on a modified bios, meaning it was code that Microsoft owned that was modified to do whatever it was made to do. The modified bios for the XBOX 360 dvd drives is illegal, however anyone opening up their system is probably not going to be installing a chip when there is no need to install one, so things like the Blaster360 are legal because they don;t contain any code made by MS.
Installing the mod chip: I suppose that much of what was said above should be said again here, however I will say it in a few shorter words. if the chip is not ilegal (as described above) there is no reason why you can;t install a chip in your console. it is your property... do what you will with it. Obviously the console makers are not obligated to honor their warranty once it has been opened. In fact, as far back as the PS1 (probably farther but I have not modded anything pre-ps1) these companies took measures of producing seals on the consoles to show if the casing had been opened... thus voiding warranty.
Using the mod chip: This seems to me like it should be a no-brainer. If you are playing home-brew and the mod-chip is legal (once again, as described above) then you are fine. You have done nothing wrong, not broken any laws, etc. if you are playing Backups games (or games we call backups but are really pirated copies of games downloaded from the internet or possible burned off a rental game) you are breaking the law. NO YOU CAN NOT make copies of your own games as backups. Many people use the word backup because they feel it will somehow save them. Technically it is illegal. Now, if the feds did indeed raid your house and found that you owned a legitimate copy of every game that you have on a burned disc, well, probably you will be fine. Game companies have bigger fish to fry, if you are not enjoying their games WITHOUT also buying them, they probably won't care. This does not mean that they are not fully within their rights to prosecute you for your "backups". If your games are illegally downloaded I think it is common sense to realize you are breaking the law. In thsi case, if you are caught, you can probably be busted for owning a mod-chip because you used it maliciously.
In an extremely general sense, think of owning a mod chip like owning a gun (if you acquired the gun legally, of course). Neither is illegal to own unless you use it for illegal purposes. In the case of the gun, shooting people. In the case of the mod-chip, playing pirated games.
I don't have torrent site invites...