One of my favorite online BS trainers is at (Dead link: http://www.blackjack-bst.com) . It throws 280 decisions at you as fast as you can answer. A real mind meltor.
Regards
Vytas
Casino Verite has 37 drills with thousands of different combinations of options. It is not online because the delays would interfere with the measurements.
The BlackJack Expert/Mentor/Counter suite of trainers from Deepnettech at http://www.deepnettech.com/ are really good trainers that you can use on a PDA as well as a PC(I practice on the toilet!). They do allow you to train on hard, soft and pairs only if that's what you want to do. You can download a good working trial but it's not obvious how to specify hand types. What you need to do is go to "File - Preferences - Stats/Tests" then choose you prefered hand type from the drop down.