lammert - 2:31 am on Aug 2, 2010 (gmt 0)
@dsjbirch: SDSL is symmetric DSL where the speeds for upload and download are the same. Most DSL connections use ADSL (asymmetric) with a much higher download speed than upload speed. That is good for surfing the Internet from a home connection. But the other way--i.e. serving a website from a local connection back to the Internet--the bulk of the data will go in the slow direction, giving a less than ideal performance. SDSL connections are in general more expensive than ADSL connections.
BGP is supported on backbone grade routers which are much more expensive than the general ADSL router. But if your ISP supports BGP on an end connection (with a large IF), you may not need such a router yourself, because the whole routing table maintenance and updates actions should be on the ISP side of your connections, rather than on your own side.
@incrediBILL: The OP requested a solution where requests for the website would be forwarded to both IP addresses with redundancy. Round robin DNS where a failing IP address is removed (call it DNS failover :)) is the only payable solution for that which I know of.
With all this having been said, looking at costs and maintenance efforts, hiring a server (VPS or dedicated) in a data center might be a much more economical exercise than trying to make an high-available end-connection to a local server.