This would not be simple at all. You would need to search for a migration tool that can do it for you.
However the data types between mySQL and SQL Server are very different so you would need to go through and correct lots of parts of the database.
The last time I did this (and I know the database inside out) it took from 11am till 4pm to get the database converted correctly and the software to do the conversion cost $299
I would not recommend that you do this, instead look for a host that does do SQL Server as mySQL is for PHP and never runs well with ASP/ASP.NET where you should use SQL Server.
Our own Hosting comes with SQL Server 2008 and prices for forum only hosting start at £3.99 and for full website hosting which you can host two full websites on at £6.99.
http://www.webwiz.net/webhosting/We also have Unlimited Website/Account Reseller Packages Starting from just £19.99 per month and come with 5 SQL Server databases.
Edited by WebWiz-Bruce - 07 December 2009 at 3:08pm