Depends.
If the DSL is ready, you will be on line as soon as you are ready. Follow instructions and all will be well. Then, dump Yahoo, the connection and SBC crap and let the PC run your DSL.
If all is not ready, the tech will have to trace your line back to the switching station only to find out your line was not upgraded or something was not turned on and have to fix it, TOMORROW.
It ain't all bad., Usually on at over 100 Meg baud, So, enjoy !