These are working for both data and mms on the $60/month unlimited plan as of April 6th, 2012.
Name: T-Mobile Data
APN: simple
Proxy:
Port:
Username:
Password:
Server:
MMSC:
MMS proxy:
MMS port:
MCC: 310
MNC: 260
Authentication type:
APN type: default,supl,admin,dun,hipri
APN protocol: IPv4
Bearer: Unspecified
Name: T-Mobile MMS
APN: simple
Proxy:
Port:
Username:
Password:
Server:
MMSC: http://smpl.mms.msg.eng.t-mobile.com/mms/wapenc
MMS proxy:
MMS port:
MCC: 310
MNC: 260
Authentication type:
APN type: default,supl,mms
APN protocol: IPv4
Bearer: Unspecified
Name: T-Mobile Data
APN: simple
Proxy:
Port:
Username:
Password:
Server:
MMSC:
MMS proxy:
MMS port:
MCC: 310
MNC: 260
Authentication type:
APN type: default,supl,admin,dun,hipri
APN protocol: IPv4
Bearer: Unspecified
Name: T-Mobile MMS
APN: simple
Proxy:
Port:
Username:
Password:
Server:
MMSC: http://smpl.mms.msg.eng.t-mobile.com/mms/wapenc
MMS proxy:
MMS port:
MCC: 310
MNC: 260
Authentication type:
APN type: default,supl,mms
APN protocol: IPv4
Bearer: Unspecified