I'm not well-versed on this topic, so apologies in advance, but here's how I was able to get an iPhone to recognize my 2wire router:
I tried inputting the dollar sign using what I thought was the appropriate password type (WEP, IIRC) but I couldn't get it to accept the password w/ or without. Then I changed the type of password (WEP hex?) even though to me it didn't seem to be the right one given how my 2wire IP address page described it, but it did the trick and I now have WiFi on my iPhone through the 2wire.
Hope that helps.