QUOTE(g0ldf1sh @ Dec 22 2010, 01:48 AM)
erm, i could brief u little abt it..well, almost all apps can be transfer to sd card in froyo, BUT not to those widget apps (beautiful widget,poweramp,typo clock,etc) because u will lost the function of the apps....
apparently, a clean rom will have around 175mb of internal storage, but with htc sense and stock widgets, it should be around 120<--wild guess
here is the example...Angry Birds
the size of the app is 16mb, so once u transfer to sd card, it would be around 2mb on phone, and the rest will stored in ur sd card..
not entirely the whole 16mb in ur sd card xD
need to create partition in the sd card as well, tht's how i did it in custom ROM, not sure about stock froyo rom...but i think the mechanism is more likely the same..
i am sorry, i am not really understand, is it mean the rest apps like games or social networking apps etc can transfer to the card? or the system will help me to filter which can transfer, so i do not need to worry for any problem occur in the future?
for ur example, what is the purpose of store 2mb on the phone? i check my phone when i get it, it got around 100mb of internal storage, but it is getting lesser very fast because i like to dl apps or games to try.

i plan to get 8gb or 16 gb sd card in these few days, is it i have to make the partition for the card as well? is it the phone can recognize for both drive? i worried it wont show 2 drives in my phone, haha.. and what is the best percentage of the partition for the card?