Do I Need To Have Phone Service To Use Dsl?

I don't think you do... It depends on the company though... But am far as I know phone service is not needed to use dsl

Various telephone companies now offer "Naked DSL," which is DSL without telephone service.

DSL basically uses a phone line to let you access the internet.  Your phone companies will want you to have both their phone services as well as their DSL service so that they can have more business.  But it varies from company to company so you would need to shop around if you want one without the other.  Before MCI merged with Verizon, I use to have Verizon as my phone service and MCI as my DSL provider.  I just checked Verizon's site, they do provide DSL service without their phone service but charges more each month.