Does Samsung Galaxy S Indian ROM (latest DDJP6) has Bengali support?
Here's a workaround using Opera Mini.

Download and install Opera Mini (OM). Try accessing a site like the one cited above - http://bn.wikipedia.org

If it doesn't work out of the box, do the following:

In the address bar, type opera:config
Navigate to the option Use bitmap fonts for complex scripts and set it to YES

The fonts and script lettering should now be visible, albeit as images instead of text. That'll make content visible, but unlike text non-selectable.