How to Open LIne fone w/ void of waranty?

Hi!
My existing network provider dont offer free GPRS so I cant access
Internet much unlike GLOBE. Im planning to make my phone an Openline
and buy a Globe simpack to access the free GPRS/ Wap for internet but
Im worried that the waranty for my phone might be void.
In the first place, would the servce center would detect that my
phone is already openline? Coz i know, there is no need to open my
fone to make it openline (they'll just insert cable). Would they?
And is there a way to make it openline w/o goin to shops (like
here..online)?
Please advise... i know your answer would be a great help to others
too :)

Thanks,
Lucy