Google is working hard to address the 3G connectivity problem in Nexus One. According to the latest response from Google Employee in the Nexus One support forum, Google is working on a software fix that should improve some 3G Connectivity problems reported by early Nexus One adopters.
If everything goes as per their plans in that software fix testing, Google will provide Nexus One 3G fix via over-the-air update in the next week or so.
Ivar, a Google Employee has said the following in the Nexus One support forums:
Our engineers have uncovered specific cases for which a software fix should improve connectivity to 3G for some users. We are testing this fix now, initial results are positive, and if everything progresses as planned, we will provide an over-the-air software update to your phone in the next week or so. It may be, however, that users are experiencing problems as a result of being on the edge or outside of 3G coverage, which a product fix cannot address.