I have got many request on how to enable bengali font too, today people are using more application like -i-leap for this purpose which dosen't have much of designing support compare to more advance word processor like Ms Word 2003 or later. Most users of such application don't know that they can enable all type of(most likely famous) language/font support in Windows. As windows comes with these packages but not defaultly installed.
The steps for enabling bengali language support is similar to enabling the hindi font. except the last step.
after installing the Supplemental language support (refer to blog : Enabling Hindi) and rebooting the computer follow these steps
Click on Start -> Settings -> Control Panel.
Double-Click on Regional and Language Options.
Goto Languages tab.
Click on Details button.
Click on Add button.
Under Input languages, click and select Bengali(india) from the pull-down list of languages.
Under Keyboard layout/IME, click and select Bengali(inscript) from the list of languages. click o.k and you are done.
In case of any problem you may write to my comments. thank you