I have an O2 Xda Exec and it was sort of easy, i found the pop3, stmp settings in the help of my yahoo mail, but then i had to change a couple of settings to make it pick up emails that were read in my yahoo email and so on.

ps if your battery life is naf, do the let it go flat, charge it up several times thing, it worked for me.

Not the best phone i've ever had but after four months its growing on me.