It seems there are some 3G Connectivity issues with the Nexus One in Singapore for M1 and Starhub customers in Singapore according to some media report. SingTel customers should not have this issue because for SingTel customers, the Nexus One should auto-connect to their 3G network (a hint that SingTel maybe bringing in Nexus One?). For Starhub and M1 customers, they will need to enter in their APN settings to connect to the 3G network by going through the following steps:
APN Settings
For Starhub customers: