Depends if were talking a new system build or your adding that SATA drive to a current system....if it's a new build then all ya need to do is change BIOS setting to boot SATA first, in your boot options, your IDE should be fine as is.
But if were talking upgrading your current system, then you'll have to add SATA drive make sure drive is recognized by both BIOS and windows, then you'll need to Ghost the image of your IDE drive on to the SATA drive, check out the website of the manufacturer of your new drive for a utility that can do that for ya, unless you have Ghost or Drive Image, it'll show how ya goes about it. After ghosting image onto new drive then go back in BIOS and set boot option to boot SATA first.
If your using a PCI SATA controller than you'll probably wanna set your boot options to boot SCSI first, since a controller card is looked as a SCSI card in BIOS.
Not sure what your situation is, you didn't leave enough detail on what "you" wanna do....so i hope that helps.