I found an article about google's GMail.
If i read the article, it seems that gmail isn't that secure as it should be.
The article says that it can be hacked with 3 simple steps (i doubt it will be simple).

Full article:

According to a report by OfficialWire, software designed to hack Google's (google.com) newly launched Gmail service was released last week, developed by a hacking group in Australia known as AusPhreak.

The software reportedly allows hackers to break into Gmail accounts by following a simple three-step process. Google, the report said, has already responded with the instigation of a visually-oriented anti-robot test.

The news comes as Google attempts to deal with criticims of the Gmail service from various advocacy groups.

Gmail, Google's free Web-based email service, was launched in April amid controversy when it unveiled plans to generate revenue for the service by using its contextual advertising technologies to scan emails and place ads related to the message contents. Privacy concerns were raised by a number of groups and the California Senate drafted legislation to limits Gmail’s capabilities.

Google's Gmail is currently in beta testing.
source: http://www.thewhir.com