As others have mentioned, Back To My Mac is probably your best bet, assuming you have hardware that supports it. (You can use it to connect either to an actual Mac or to USB-attached storage on the AEBS itself.) The AEBS does not have a built-in VPN server like you'll find on some routers, which is what I think you're really asking about, but Back To My Mac comes close.
You can also use a VPN server running on OS X Server and configure the AEBS to port-forward the relevant ports to your properly-configured VPN server (really, you can use any router that supports port-forwarding and any VPN server, but OS X Server will configure the AEBS for you if you let it). Whether this is worth it or not depends on what you were hoping to do with the VPN in the first place. This is the option I take because I have several devices on my home network with private IP addresses that I don't want to expose to the Internet directly but occasionally want to control remotely, and a VPN connection allows me to do that since it's just like I'm on my LAN.