how to install a better rom when i cant match the rom i got

[Guest pantic]

hey hows it going im daniel nice to meet you all.. :)

i've got 2 pda's

Sony Ericsson Xperia X1a

Samsung Omina SGH-i900

i love the layout of the xperia and i love the layout of the i900

Omina

PDA I900MBHJ3/MBHJ3

Phone I900XXHJI

Xperia

no idea how to get the version of it

i would like to intergrade the auto network operator settings to the omina and maybe go to windows 6.5 if its better?

i use the omina as my business phone so something with more business settings would be better

my main questions

1. how do i change my rom on the omina to a more used one as mine is a modded one by the 3 network

2. and whats a good rom i should learn to play with that has all the sorta features im looking for?

3. is there any fully functionally linux roms for either the xperia/omina?

thanks for any feedback i get :)

[Guest chakam]

I know this post is a little old now but I have a very similar issue. is there anywhere someone can point me to or explain?