iphone sdk tabbased application?
i have two questions:

1>can anyone suggest me a good tutorial for:

ViewTransitions (transitions between 2 views)
- all variations (curl, flip etc)


2> i am making a tabbased application where i have navigation in each tab, i hide it but now i have to put a png of back button where previously navbar was present .. how can i put that custom png and how to redirect it to previous page...



thanks in advance... 
iphone sdk tabbased application?
===

i have two questions:

1>can anyone suggest me a good tutorial for:

ViewTransitions (transitions between 2 views)
- all variations (curl, flip etc)


2> i am making a tabbased application where i have navigation in each tab, i hide it but now i have to put a png of back button where previously navbar was present .. how can i put that custom png and how to redirect it to previous page...



thanks in advance... 