1) It is important to tie technology to the objective because we do not have time to waste doing an activity for activity sake. We have the highest stakes testing that we have ever had and we have to cover more material then we have ever had to cover. If the technology doesn't help them learn the objectives we don't have time to use it.
2) Students have to be held accountable or they will not do it. If you give the students access to the internet and you are not watching them or asking them to complete something they will will get off track because that is just human nature.
3) I like Chemgametutor.com it could be a good review station or if students are finished with everything for the day they could go and review using the game. Since I can have student logins that track their progress I can see exactly what they are doing and which kids are not doing well on a particular topic.
I also like pHet you can use it to reinforce a topic that you are covering. Many of the simulations allow students to see what is occurring on a molecular level which helps students make connections. To hold students accountable I can make a worksheet that goes along with the activity that they would turn in (or have on google docs and turn in electronically). Not only does this keep them on track but it also has them focus on the parts of simulation that I find important and that are aligned with my objective.
4) As far as ipad apps that I like: Mahjong Chem, I've tried to use this on the i-pod touch but the tiles are too little to see so this would be better on the i-pad. This a great review app and students can complete this at one station and put their score and time on a sheet of paper to see who has the highest score by the end of the day. I also like Formulas. I recently used this in class on the i-pod touches when students were done with their other work. It gives them immediate feedback if they are correct or not.
5) Students can also use the i-pad to view videos as a station. These videos can be of new material, a short video clip about things we are discussing in class, or student created review videos.