The situation:

I have wireless access point A connected to the Internet by a DSL connection. I also have wireless access point B connected to computer A with a wire. There is no connection between wireless access point A and wireless access point B.

The problem:

I want computer A to use wireless access point B to connect to wireless access point A and share the DSL connection. I have set both the wireless access points to have the same ssid and channel but the access points won't connect. Can anyone suggest what to do now?

You would actually need a third device to connect the two access points together. My WAP by linksys would be able to work this way. Suggestion: use wireless card for computer A and make life easier.

Typically AP's won't try and connect - it's not their function.
I believe the bridging functionality is built into some Routers/APs - at extra cost. In the case of bridging different subnets, I guess both ends would need to be aware. Don't know, just a guess on my part.
I achieved what you want to do by making AP-B a repeater. Again this functionality is hard to find. I bought the AP off a mate because I could use it this way. Doesn't have an ESSID as in repeater function it "knows" it doesn't need one - uses the ESSID of the router, which does DHCP for everyone. Extends my network transparently.