Here is the Tricks........
1. You can connect your mobile through PC (Mass Storage) or Using X-plore from mobile.
2. If you don't have X-plore then download from Here . Install it in your mobile
3. Go to E:/Resources/Fonts
3. If there is no Fonts folder then create it Named "Fonts"
4. Now download this fonts from Here
5. Extract .Zip file by Zip Manager or PC. Download Zip Manage for S60 from Here . Install it in your mobile Memory Card
6. There will be 4 fonts inside.
7. Now copy these 4 fonts to E:/Resources/Fonts
8. Restart your mobile & Enjoy!
9. If You like it then share it :)
Here's Some ScreenShot of Bangla fonts in UC Browser