Is it ok to use a standard dc adapter from somewhere like radio shack with effects pedals?
As long as it's the right polarity, supplies enough mA to satisfy the pedal's current draw (more is fine, less is no good), and is of course the right voltage (You want 9V, of course).....
generic ones are usually noisy little buggers, but yeah if everything matches up use it.
^Yeap, that's always an issue with unregulated power supplies.
Yeah should be fine. Don't mess up the polarity though, guitar pedals tend to deal very badly with it and you could easily turn a $200 overdrive into a $200 paperweight.