Just wanna know if they're really usefull, if they help to improve the image a little bit in HDTV

Ps: Please go to vote for the biggest New Super Mario Bros Wii fan here: http://www.vgchartz.com/forum/thread.php?id=91188&page=1

Help Wii_Master or sink him more 

component cable are worth it if you have an HDTV, the improvements are noticeable, my component cables are not working now and playing with the regular cables is hurting my eyes.

Component cables >>>>>> composite ESPECIALLY on HDTV.

however, final results will vary based on your TV. I have a pretty good HDTV and the Wii in 480P looks fantastic.

stealing the thread a little bit here, are there similiar cables for the PS2?

Mario Galaxy looks beautiful.

You can only get 60 FPS with component cables.

You can get component cables for like $8 online now. Even if the improvement was small(which it isn't) I would get them.

Yes! :). You can then change to Progressive output, assuming your TV is new enough. Colours are richer as well. It's like chalk and cheese on my Bravia.

Nope, it has a special Wii head.

Yes, they can make quite a nice difference, but as has already been noted it does depend somewhat on the quality of your TV. I got the Nintendo ones and some cheap ones and there is no obvious difference in image quality.