Don't do it. With current chipsets and drivers, SSDs in RAID do not get the TRIM command and performance will degrade over time.
Note that some will disagree with me, saying that the drive's internal garbage collection will be sufficient.
Finally, if you do use RAID0, remember that it is more likely to fail than single-disk configurations, and harder to recover data in case of a failure. Do frequent backups.
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That said. If the drives are new and don't already have data or your system on them, and they will be your boot drives, first disconnect any other drives from your system. Then attach the two SSDs and set the drive controller in the BIOS to RAID mode. When you reboot, look for a BIOS message to the effect of "press Ctl/A for RAID configuration" and press the relevant key. The menu that it gives you should be sufficiently clear to build a RAID from the two drives.
Then put your Win7 DVD in the drive, boot from it, and do an install. The Win7 installation is savvy about drivers needed for RAID and AHCI.
If this is an existing system, and you want to keep the existing OS installation, that's another question. Let us know.