GregSQL
The first definately can be done. Double click the chart layout. Then right click on your x-coordinate field. Click properties. I don't have reporting services in front of me so I'm going by memory, but there is an option -- I think on the general tab -- to turn off the actual values of the data.
Number two is more difficult however. I don't think Business Intelligence Studio has anything that will accomodate this. You may be able to do something with the report viewer in Visual Studio to handle the on mouse over event. However, I doubt it would be able to "pop up" the actual value that you are hovering over.