Hi
As LadyJessie has said, you really need to get advice based on your own specific circumstances to avoid making a big mistake.
From my own research, there are a few general things to note:
Domicile is very difficult to change - it is generally where you are born or, in some circumstances - your family's home country.
Residence is the thing for you to look at. These days, it is dealt with initially looking at tax years (ending 5 April). If you leave the UK and return after a complete tax year has elapsed you can be non-resident for the period you are away. In other words, if you go away on 1 April 2008 and come back on 10 April 2009 you are OK. If you go on 1 May 2008 and come back on 10 May 2009, you are not.
The next thing to consider is time spent in the UK during the period of non-residence as too much time in the UK may lead you to be treated as resident after all.
This is something where the rules have recently changed in that, you used to count the day of arrival and departure as days out of the UK but now that is not necessarily the case.
The Revenues guidance is that someone is resident if that person is in the UK for 183 days or more in the tax year;
or
the person visits the UK regularly and after four years the visits during those years average 91 days or more a tax year.
However, for this purpose any days spent in the UK for exceptional circumstances beyond the person’s control, for example, the illness of the person or a member of his or her immediate family are ignored for the 91 days (but not the 183 day test).
It also seems that, if you are resident in the UK, you are taxed on your 'world income' via your UK return and will get credit for the tax paid at source on the overseas income up to the level of UK tax due on it.
If you are not resident, you are still taxed on your UK income in the UK.
Hope that helps.
I hope someone else more versed in these matters can come along and add to the debate.

D