I came across this problem, that in my android phone, i was not able to connect o gtalk, whatsapp, maps etc, whereas I was able to browse internet via browser.
The reason I found out was that I came across a wifi connection sometime that blocked my phone apps from connecting to internet. After that, even if I use data connection via sim, I was not able to use internet based apps.
The solution is:
go to
Settings->Wireless and Networks ->Mobile Networks-> Access point names
Now, right click and select 'Reset to default'.
That's it, now I was able to connect these apps to internet.
