ereg_replace() problems

[pieterprovoost]

Hi,

I would like to use the ereg_replace() function to replace wiki-like
syntax, for example:

[[somepage]]
becomes <a href="index.php?page=somepage">somepage</a>

**hello**
becomes <i>hello</i>

The problem with the first example is that "somepage" occurs twice
after the replacement, the problem with the second example is that the
opening and closing tags "**" are identical. Can anyone refer me to a
good page on ereg_replace(), or help me with these examples?

Thanks,
Pietrer