IP Address Issues

I'm working on my first black hat SEO initiative. One of the requirements of the venture is to change an ip address at will then access a website and submit a form.

What's the best way to go about doing this. I'm working with iMacros for auto form submission and I can obtain a list of web proxies but how do I go about changing the proxy via iMacros?

Does anyone have a suggested method to pull this off?

For those interested in the solution to this question, I did manage to finally solve this.

1) Setup WAMP to add PHP to a local server.
2) Download some free-ish software that allows you to verify large lists of proxies.
3) Create a proxy download script in iMacros that hits a dozen or so websites and extracts the public proxies.
4) Verify the 30,000+ proxies you now have extracted via your imacros script in step 3 through the software in step 2. Store the verified list somewhere for your future php/iMacros scripts to use.
5) Create a set of iMacros scripts to swap the proxy in firefox and test the one you currently swapped to (public proxies go down quickly so you need to re-test the given proxy just in case). Verify your current IP against any of the free-ip tests available on the net and use an extract in iMacros to return the value(s) to php.
6) Create a blacklist on the fly to avoid using the same ip-address/proxy (and your personal ip address)
7) Wrapper this all up into a sexy php class that you can include in future scripts to simply "getNewIP()" and you are done!

I did get some private messages for services that offer this but it is easily conquerable solo given lots of free tools (except for the iMacros registration...but you could just use the trial edition as I am on).

-Tester

i HAVE been trying to do this for months, and slowly making progress. but would love to know where you have taken it.

You might want to check out my http://www.blackhatworld.com/blackhat-seo/proxies-sale/107493-new-exclusive-http-proxy-service-api-multiple-subnets-auto-browser-configuration.html for seo-proxies.com in case you want a professional proxy solution for your IP troubles.
There is a free iMacros example-bot included that shows how to add rotating proxy support.

If you don't want exclusive proxies you'll need some public source or a shared alternative.