I have some paypal,I want to exchange to mb,how can I do that?

I have the same question.

Simple. Add a bank account to both your paypal and moneybookers accounts.
Withdraw to the account and upload to Paypal or Moneybookers.

you won´t find a regular service which offers this because it´s against pp´s and mb´s tos. maybe you´ll find someone in privat or as said before: withdraw t bank account and fund then from your bank account