Basic PHP Issue / syntax for custom addon.

I am trying to fix an issue with zoints tags module to make it FULLY vbseo compatible.

I know from the vbseo functions that I can make a call to vbseo_any_url() to convert a url to a vbseo url. (i think i remembered that function name right)

My trouble is, I have a massive long string of text and html - inside which are several urls...

What would be the syntax to loop through each url (regexp maybe) and to pass each url through the vbseo function, and then put the replacement back into the text.

Hope this makes sense, but I'm stuck.

Is this long string a html-formatted code part with <a> tags embedded or it is a plain text?

<a> tags and all

in this case it would be better to use make_crawlable($text) function to rewrite them all