The Android's App2SD capability is a little bit stupid.
Some apps, such as widgets, cannot be installed to SD. Even for those that you can install to SD, parts of the app still remains in the internal memory. For example, the dex file and (usually) the data still remains in internal mem, while the apk and lib gets moved. Some apps will stupidly keep their data (eg, Chrome and the Straits Times app) inside the main app storage, taking up several hundred megs of precious space.
The advantage of App2SD is that it does not require root, you don't need a 2nd partition, and most backup programs can handle it well.
Another option is to use Link2SD. You have to pay for it, but it's superior in almost every way. It's better in that all apps can be moved to SD, and even the dex file is moved, so you save more space. The disadvantages are that 1) you need ROOT, 2) you need to create a 2nd partition in your SD card, and 3) not all backup programs know how to handle the 2nd partition.
Got my hongmi last night. installed framaroot and rooted phone. Installed app2sd app. Installed a game and using app2sd tried to transfer game app to sdcard. It said successful but further checked the storage the app was still in the internal memory. any ideas?? Need to create partition on sd card?