submit url

HI

I am developing an installer for myapplication.
IN that installation i have a page which asks client to enter for username and phone number and emailid then i have to take them and i have to submit them to url something like this:

"http://www.sace.com/servlet/servlet.WebToLead?encoding=UTF-8&oid=00D3
I1&retURL=http://www.webpartner.com/ply.html&first_name="
+ sFirstName + "&last_name=" + sLastName + "&email=" + g_szEmail + "&phone="+g_szUserPhone;

Here sFirstName and sLastName are entered by the user.

How to this in NSIS script

Thanks.

Use InetLoad plugin.

-Stu