Actually this matter was a brain teaser to me also.Do u believe this?.To pacify this teaser,u must do only 3 steps.So Lets do it instead taking bilge... 1)Download the Opera mini 5,6(latest version is 6.1)
2)Install it ti ur mobile & plz type config: or opera:config in address bar & go
3)In opera settings u’ll notify “use bitmap fonts for complex scripts” option.change it to yes.Then save
That’s it’...Enjoy it....It has some rendering issues.Never mind about that.
If u have an Android smart phone u can test this method.plz refer this kalinga’s blog. http://sinhala.kalingasblog.com/2010/07/25/sinhala-unicode-on-android-google-nexus-one/#more-738 or easily u can download SETT web browser which supports to Sinhala Unicode now. http://code.google.com/p/sett-browser/ 
