Looks like you need an APN of just "phone" to get the faster speed. Read this at anandtech;
http://www.anandtech.com/show/4971/apple-iphone-4s-review-att-verizon/3
Saw some other phone notes needing this change to get the faster speed on the net too.
I tried to change the APN to phone but got the message you aren't subscribed to cellular data.
As most know by now the go phone SIMs require wap.cingular to get data.
http://www.anandtech.com/show/4971/apple-iphone-4s-review-att-verizon/3
Theres one last tangential question about HSPA+ on the 4S, specifically on AT&T. Ive left this to the end since it doesnt impact non-US 4S users, but the last question is whether the 4S is actually on HSPA+. For a while, I was concerned that AT&T would continue using the wap.cingular APN on the 4S which seems shaped to around 7.2 Mbps HSDPA. Im glad to report that AT&T hasnt continued using wap.cingular on its 4S data plans, instead using phone which is a newer APN that allows for HSPA+ (above 7.2 Mbps) rates. You can check this yourself under PDP Context Info on the 4S in field test.
Saw some other phone notes needing this change to get the faster speed on the net too.
I tried to change the APN to phone but got the message you aren't subscribed to cellular data.
As most know by now the go phone SIMs require wap.cingular to get data.