All users who had their orkut acounts linked to Gmail acounts allready had the advantage to chat with their friends inside orkut but the users who use orkut with non Gmail Google Accounts can from now on chat with all their friends inside Orkut with their non Gmail ID's...
A post on Google Talkabout blog explains how>>
Hi Orkut users! For those of you who didn't have Gmail enabled for your account or use a gmail.com user name, you may have found it odd that Google Talk was not available in Orkut for you. Well, now we are enabling chat for all Orkut accounts, without the Gmail requirement. Any Orkut user will be able to chat on the Google Talk network using their existing email address as their user name! We are in the process of turning it on for everybody, so if you don't see it yet then it's coming soon.
For added security, we require a simple email verification to use this new feature. Click here to learn how to verify your account.
Those of you who have been paying closer attention might have noticed that chat for non-Gmail accounts already works in the new version of iGoogle (available for some users, coming soon to everyone). The Talk server team has been working behind the scenes to make this possible. We've engineered a solution that allows you to chat using an email address that is not hosted at Google, while preserving our existing interoperability with 3rd party XMPP clients and server-to-server communication with other XMPP networks.
Talk in Gmail is great, and we are really excited about putting Talk in other fun and useful places. If you already have a Google account, you're all set.
All those users who want to shift to a single login for their email and orkut can just go to gmail.com and login with their non gmail orkut login ids and then u'll be given an option to create a new gmail id which you can make your primary id's and can shift to a single unified solution.