Extending you home, small business, data center, co lo, or enterprise offices to AWS running VPC, you will probably want to run an IPSEC tunnel. AWS lists the certified VPN devices here: http://aws.amazon.com/vpc/faqs/#C9. However, if you are doing this from a home or small office connection, you may not want to use an expensive dedicated device. In this case the open source pfSense makes sense: www.pfsense.org. It can used to create an inexpensive IPSEC tunnel to AWS VPC using any hardware you have 'laying around'.