i will answer ur first question only..

update via internet.. u will need a software called SEUS.. u can get it from se website.. install it, then run it, then follow the instruction from there on..

I haven't got this kind of problem on my phone for video ringtone. BTW, im using 3gp format for my ringtone. Why dont u try to set the phone demo video as your ringtone as it is in mp4 format. If its ok, I guess the problem is comes from u the clips u're using.

You can toggle the screen size from the options, whether horizontal or vertical. I guess that's what you meant, right? 

go for other model k610i website and download seus from there.. most probably they dont update the website.. and mostly i believe k618i can use seus too.. like w900i website also dont hv seus but i able to update my w900i using seus..

i have dl "Download Update_Service_Setup-2.6.11.7.exe"  from the following link
http://www.sonyericsson.com/spg.jsp?cc=my&...839&numItems=18
n i have try it at my campus computer but something wrong... after install n load the program,it post up n said need to update... then after updating for 21%,it pop up another message that get a newest version or something like tat... wat happen?

I have the same soft ver as yours.  Tried to update it stated that I got the latest soft already.

I got 2 days if I enable both GSM/3G network. Double that if I disable 3G network.

ouch..I found another problem with my phone.. When an unknown number miss call or i call an unknown number(not in address book), it will not be recorded in calls section, this is very very inconvenient when asking for number... =.="

Or do I need to set anything, have read everything in the settings but none related. sigh...

1. R1ED001 shud be latest.. i am not really sure if there is further later firmware though,, google abt it.

2. search in garagesales or google sonystyle.com, you can get the answer for sony M2 there. brand other than sony? sandisk. price is slightly cheaper. you can find all these info you want in garagesales.

3. shud be 1gb at the moment, but then if 2gb is available in market (it is but no one tested it yet or else i am so lazy to google details for you), theoretically it shud support up to 2gb then.

4. it wont lag the performance of the phone except during startup and when you access the files explorer especially when u have used up to almost full memory space. reason: it takes more time to read 100 files compare to read 2 files only. make sense?
5. these are settings/profile for the mms, 3g, grps etc. you will need to install them into your phone the gprs, mms, 3g to work in your phone with your service provider.

Mine is the same... only normal network.. no 3G settings.. but nothing to worry, jz download settings lo...