MAXIS

1) Home -> Menu -> Settings -> Wireless & networks -> Mobile networks -> Access Points Name
2) Menu -> New APN

Name: Maxis 3G Internet

APN: unet
Proxy: 202.075.133.049
Port: 80
User Name: maxis
Password: *** (I don't know what is the password as it only shown *** on my SGT)
Server: Not Set
MMSC: http://172.16.74.100:10021/mmsc
MMS Proxy: 202.075.133.049
MMS Port: 80
MCC: 502
MNC: 12
Authentication type: PAP
APN type: internet + mms

DIGI

1) Home -> Menu -> Settings -> Wireless & networks -> Mobile networks -> Access Points Name
2) Menu -> New APN
Name : DiGi Internet
User name : digi
APN: diginet
MCC: 502
MNC: 16
APN Type: default
(Others, blank)

NOTE : If you subscribed to Digi Internet Prepaid package ( RM2/day package ): the APN is : 3gdgnet

DIGI MMS

Name: DIGI MMS
APN: digimms
Proxy: no set
Port: Not Set
Username: mms
password: mms
Server: http://mms.digi.com.my/servlets/mms
MMS proxy: 203.092.128.160
MMS port: 80
MMS protocol: WAP 2.0
MCC: 502
MNC: 16
Authentication type: not set
APN type: mms

Digi Wap

Name: digiwap
Apn: digiwap
Proxy: 203.092.128.188
Port: 80
Username: digi
Password: digi
Server: Not Set
MMSC: Not Set
MMS proxy: Not Set
MMS Port: Not Set
MMS protocol: wap 2.0
MCC: 502
MNC: 16
Authentication Type: Not Set
Apn Type: httpproxy
CELCOM

1) Home -> Menu -> Settings -> Wireless & networks -> Mobile networks -> Access Points Name
2) Menu -> New APN
Name : Celcom 3G
APN : celcom3g
MMSC: http://mms.celcom.net.my
MMS Proxy : 10.128.1.242
MMS Port : 8080

Can try this if above doesn't work:

Celcom 3g internet setting :

Name : Celcom 3G Internet
APN : celcom3g
MCC : 502
MNC : 19
APN type : default

Celcom 3g MMS setting :

Name : Celcom 3G MMS
APN : celcom3g
MMSC : http://mms.celcom.net.my
MMS proxy : 10.128.1.242
MMS port : 8080
MCC : 502
MNC : 19
APN type : mms

Celcom 2g internet setting :

Name : Celcom 2G Internet
APN : celcom.net.my
MCC : 502
MNC : 19
APN type : default

Celcom 2g MMS setting :

Name : Celcom 2G MMS
APN : mms.celcom.net.my
MMSC : http://mms.celcom.net.my
MMS proxy : 10.128.1.242
MMS port : 8080
MCC : 502
MNC : 19
APN type : mms