The launch campaign encompasses print work in The Sun, Metro and The London Paper and online, outdoor and ambient executions.
The creative promotes the launch of the phone through giant Google Mobile map icons appearing in quintessentially British locations with speech bubbles declaring "It's here. The new T-Mobile G1 with Google".
The giant pins also appear online, in an accompanying viral campaign.
Saatchi & Saatchi paved the way for the T-Mobile G1 with a pre-launch print campaign and an online competition to drive registrations.
T-Mobile G1 is the first mobile phone that runs on Google's Android operating system and boasts a large format screen, Qwerty computer keyboard and 24/7 automatic internet access.
Sam Taylor, head of advertising and sponsorship at T-Mobile, said: "We're enormously excited about the launch of the T-Mobile G1. It represents a massive step forward for mobile internet technology.
"We're delighted that the campaign has succeeded in capturing the functionality, simplicity, interactivity and - above all - the user-friendliness of the product itself."
Richard Huntington, director of strategy at Saatchi & Saatchi, said: "Our task as an agency is always made significantly easier when we're working with brilliant, breakthrough brands and products.
"And that's exactly what the T-Mobile G1 is. Our strategy was simply to bring the user-focused innovation at the core of the product to life - in an inspiring way, across the full spectrum of media touchpoints."