CONGRATS! 

to check your Android version, go to settings -> About phone -> Software information

app2SD is a built in feature from Froyo (Android 2.2), if you are on 2.2,
then you should have app2SD already
to check if you have app2SD or not,
download Quick System Info.

if you are going for a new memory card, no matter what size you're going for,
make sure you're going for the highest class available,
higher class = higher read/write speed
higher storage memory card wont slow down the phone, but low class card might.
I'm using Kingmax 8GB Class10, pretty satisfied with the performance.

if you don't root your phone, you wont void your warranty, and vice versa.

em.. if I get your meaning correctly, yea the class is the number "10",
there are different classes though, 2, 4, 6, etc..

sadly, there isn't any hole for hanging accessories,
except maybe if there's any phone case that has the hole built in,
which I haven't seen any of it.

if you're really desperate to hang your accessory on your phone,
what you can try is, get a phone case that has holes then you try to can hang your accessory on it,
personally not using any hp accessories, so I can't help much

for charging battery, about 8 hours should be good,
also you might want to calibrate your battery while you're at it,
link on how to do battery calibration here.

If your screen can rotate, then there shouldn't be any problem with it already,
it might be slow because you're not used to the orientation yet?
do note that the default homescreen of Desire won't rotate like what edwinlcw said,
if you want a rotating homescreen, you can try other homescreen, such as LauncherPro, ADW, etc.

the CN Thai keyboard settings, is the settings for the CN Thai keyboard (duh)
same as Vietnamese IME,
CN Thai is for inputing CN and Thai characters,
if you're not using it, you don't have to bother with it.
also, just in case you didn't know about this,
you can switch your input keyboard by long pressing on any text input area (e.g sms space)
then it will prompt a window saying "Input method",
click on it, then you can choose the keyboard that you want to use from there.
btw a small tip when inputting text, you can use the track pad to navigate between letters
just in case when you typed wrongly, instead of pointing at the word, you can use the track pad

hurmm...need to restore 1st then only can use mybackup...no idea already how to restore my SMSes...
i forgot the name of the casing...got 1 brand which has a hole to hang accesories to your phone...tomorrow i'll check it at digital mall...

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Added on December 14, 2010, 12:51 amat last...i can restore back my SMSes...how stupid of me not restoring dialer storage... *facepalm*

suddenly remembered the brand's name...it's Momax...here's a link to it...
http://www.lelong.com.my/Auc/Archive/Detai...ductID=63106124

the safety of your phone is the main concern...i bought my casemate tough and it saved my phone few months back when i was involved in an accident...

u use facebook? most probably that's yr sync issue..

hv u tried browsing the android market? there's lots of apps i believe for your file/folder mgmt

and try update yr facebook to the latest version using android market.. in the meantime, just stop all yr facebook sync or other accoutn sync & see if the error disappear or not..

you can use astro file manager...quite easy to use sis...(you are a girl right?later silap panggil plak...  )

for ringtone you can use ringdroid sis...

use rockplayer for watching video..