Help With Search Box/form

[William]

Hi i am trying to create a search box on a site which will take you to the following page when you click the submit button:

www.mysite.co.uk/shop/compareprices/searchterm.htm
"searchterm" being the variable submitted in the search box

At present i have the following search box/form:
<form style="margin-bottom:0;" action="http://www.mysite.co.uk/shop/index.php" method="get">
<input name="ps" type="text" value="Enter Keywords" onfocus="if(this.value=='Enter Keywords'){this.value=''; this.style.color='#000000';}" size=18 />&nbsp;<input type="hidden" name="sv" value="1" />
<input type="submit" class="srchsubmit" value="Go" />
</form>

This takes you to:
http://www.mysite.co.uk/shop/index.php?ps=searchterm&sv=1

I have already got the mod rewrite working all i need is a searchbox/form which will take you to www.mysite.co.uk/shop/compareprices/searchterm.htm when submitted.

is it possible to do this?

Any help appreciated.

William