Chinese Big5 and GB encoding

[ForzaGrifo]

Would UTF-8 (8-bit encoding of Unicode) be the answer? But what if a post is made with Big5 or GB?

[ForzaGrifo]

I would like to have my board support BOTH Big5 and GB encoding. I have several questions regarding the implementation of this:

1. Is it possible to make them interchangeable? Can the user select the encoding of their choice (Big5 or GB) on their browser (e.g. View->Encoding on IE) and the correct text (Traditional Chinese or Simplified Chinese) will be shown correctly on the page?

2. When user make a post with, say, Big5 (Traditional Chinese) characters, how can I display it as GB (Simplified Chinese) characters when the post is made? Or is it even possible to do that?

I really want to make the board interchangeable between Big5 and GB. Any feedback would be much appreciated.