Form That Filters and Replaces into a textarea

[Rockonmetal]

Ok the Form That Filters and Replaces into a textarea is my goal.
I am looking for a simple thing where I put the phrase in (Which will be the same except for the user input parts), and i click replace. and Wala! it turns it into something like.
before:
&First+Name=userinput&Last+Name=userinput
after:
<firstname>userinput</firstname><lastname>userinput</firstname>...

Anything that can do that?
I would greatly appreciate it

[Rockonmetal]

Oh and btw (by the way) it is for my own personal use. So
It doesn't have to email, mailto, unless it really needs to. This is just a converter not a specail sender.