A way to open 2 Google accounts simultaneously

In case that we have one personal account and another one company account -- for example.

We can use multiple web browsers to separate accounts. But if we want to use only one such as Firefox. This method can be a solution:

Personal-account set

• iGoogle: by this time it's not available to company account yet.
• Gmail Notifier

Company-account set

• Google Talk

Gmail Notifier and Google Talk call Gmail at different places despite of same "www.google.com/...", no matter company has set alias to another URL or not. And then from Gmail, each session links to within its own place for other services (Calendar, Docs, Sites).