Google Talk on Samsung Galaxy S II I bought a Samsung Galaxy S II, and it comes with the IM application for instant messaging, but the only messengers available are Windows Live Messenger and Yahoo! Messenger, and I couldn't find any Google Talk application on the market.

How can use Google Talk?
There is no Google Talk app within the Market. Google Talk is more or less wired to the Android release. It's usually an icon in the app drawer simply named "Talk".

Your phone seems pretty locked down by the carrier (or somebody else). If it really came without Google Talk, which would be pretty uncommon, your only chance is to install the Google Talk apk manually.