At least when you're using bitcoind, the best solution is using the sendmany RPC call, which allows you to create a single transaction that does many payouts. The transaction will be much smaller (in bytes) than the many single-payment transactions you had in mind (over 6 times, for 100 outputs), resulting in lower fees in total for the same effect.
If you are using Electrum
In Electrum you can use the CSV import feature to make bulk payments. It can accept either a CSV file or CSV entered into a text box.
This feature has been merged into the 1.9 version that is not released yet, but you can use it already.
https://github.com/spesmilo/electrum/pull/282If you find this helpful donate : 1Lo68CyAqyuEYuZ6Lbk6yndik79tfo2rYz