I have a unicel 1400 i and I want to use it as an at&t phone is that possible if so how

I would check your T-stat. It's possible that it is still sending 24 volts down to the W terminal.

Unicel GSM Internet Settings

GPRS APN: apn.unicel.com
WAP Gateway: 63.99.231.135
MMS Server: mms.info2go.com/servlets/mms

You need the T-Mobile settings if you are using a T-Mobile SIM. assuming you are in US as Unicel not over her in UK so the settings are:

T-Mobile GPRS settings (T-Mobile EDGE settings) T-Mobile GPRS/EDGE settings for terminals (e.g., phone handsets). Some items are possibly Nokia-specific. I have found the authentication type can be either Secure or Normal. These settings should be useful for T-MobileWeb users.
APN: wap.voicestream.com IP address: 216.155.165.050 Data bearer: GPRS Username: [none] Password: [none] Authentication type: Secure Connection security: Off
APN is the GPRS Access Point Name.
T-Mobile GPRS/EDGE modem settings T-Mobile GPRS/EDGE network settings when using a device as a GPRS "modem", that is, when "tethered" to another device. Examples include connection via Dial Up Networking (DUN) Bluetooth profile, or via Universal Serial Bus (USB). These settings should be useful for T-Mobile Internet users.
APN: internet2.voicestream.com Username: voicestream Password: [none] SMTP server: myemail.t-mobile.com
APN is the GPRS Access Point Name.

t-MobileWeb settings:
Primary IP address: 216.155.165.050
Secondary IP address: (Blank)
Access Point Name (APN): wap.voicestream.com
Data bearer: GPRS
Profile name: GPRS
Username: (Blank)
Password: (Blank)
Home page: myvoicestream.com
Picture messaging settings:
Multi-Media Service Center (MMSC) address: http://216.155.174.84/servlets/MMS
Validity period: 72 hours
Hide ID option (if option exists): set to off, no, or disabled

You may need to get a newer SIM card the Shine is 3G and some 3G phones don't like none 3G SIMs

its might still locked try this site

try www.mobile2mobile.net, www.unlockitnow.com or take it to a mobile service center to have it unlock for a small fee.

since ur phone i sim locked with cingular and now changed to unicel it happened,u contact any cingular center where in they can help u r problem regarding network migration..
ne other probs do tell me n do rate me..
thanks,
cya

same problem

the subsidy code for my phone is 156226. hope this works for you!