Is Gtalk communication encrypted?

What is the level of security offered by gtalk against eaves-dropping?

According to Wikipedia everything is encrypted except the HTTP connections.

The connection between the Google Talk client and the Google Talk server is encrypted, except when using Gmail's chat over HTTP, a federated network that doesn't support encryption, or when using a proxy like IMLogic.[8][9] End-to-end messages are unencrypted.[8] Google plans to add support for chat and call encryption in a future release.[10] Some XMPP clients natively support encryption with Google Talk's servers. It is possible to have end-to-end encryption over the GTalk network using OTR (off-the-record) encryption.

LifeHacker has an article on how this can be achieved using SSH.

Not guaranteed; Symantec IM Manager (discontinued now) was able to store logs of all "corporate messaging" and included support for Google Talk. Whether it covered the audio is not something I know about. If they could do it, there's probably multiple products and ad-hoc methods that can do it.

Update by user2876962:
Symantec IMM has been discontinued. One option is Actiance Vantage and few others are listed at Symnatec IM Manager migration paths.