search and replace substrings within str

[petje]

Hi,

I have the string:
...bla bla in this #exclass-3# i'm extremey good, it helps to know a little about #disclass-2# and #disclass-3# but further bla bla bla...

Now I want to read the bits in between the '#' pairs, convert those to different content, like a link, then replace the complete '#' pairs plus content with the link. so the output would read like:
bla bla in this #<A href="exclass.html#3">expertise</A> bla bla..

I've played around abit with strstr() and exploding/splitting the string but I have the feeling this could be done easaly.. any help on how or where to start would be appreciated..