Abt speedy talk and Stuttering?

Hai my name is arun from india..i am a s/w engineer..my pblm is speedy talking and stuttering......so whn i speak english i will become tensed and my talking speed increases and sometimes stuck with some words...so tht listeners cant get wht i am saying....i really fed up with ths..i tried to slow down my speed..bt i couldnt.....As i said i am an engineer...so i hve to present plenty of seminars and projects..bt due to ths prblm i cant face people andgo for job,,,i am still unemployed... so plz help me.....