@complete:If you open one of the entities or screens in your solution you will find there is a "Write Code" button at the top right of the entity or screen editor [Ctrl+Shift+W] whose menu changes according to what you currently have selected (the entity, an attribute, the screen, a field on the screen etc) and this leads you to all the events that happen during the execution of your application.

You can also right-click on an item in the solution explorer and choose "View Table Code" or "View Screen Code" for a more "traditional" route into the code editor.

You can customise LightSwitch applications extensively, not only in the look and feel by using different themes and shells but also in the behaviour of the application by writing code or using Custom Controls.

Behind the scenes LightSwitch uses MVVM and EntityFramework so you can use just about any coding methods applicable to those situations.The front-end is Silverlight (or HTML/JavsScript for the new "mobile" clients currently in beta) so you are restricted to that for the most part but server-side application code can be written using the full power of the .NET environment.