I have two email accounts set up on my phone. One is hotmail and the other O2. Both work fine.
I don't think either support 'push' so I have turned that off and have set the phone to check for new mail hourly on both accounts but, it doesn't happen.
Occasionally mail will come through on it's own but generally I have to manually check. Am I doing something wrong or is this just a quirk with the iPhone?

Good question I set mine to alert me every 15 minutes if you set it for shorter time apparently it's a drain on the battery.

Saying that a problem I have is I have x2 yahoo address x1 googlemail address linked to my I Phone however on one of the accounts it will not allow me to reply - yet all my settings are the same it just keeps coming up with an error message asking me to check my settings

It used to work fine before the iOS updates came along. Now it's just random no matter how it's set on my 3GS.

They broke more than they fixed with that stupid update, especially on the 3GS. I now show 1 bar even with no signal.

You may have a point there because I never noticed a problem before the recent update. Also before the update the mail program used to just show the inbox for each account but now it shows the two plus a global inbox AND all the account settings at the bottom of the page. Maybe it'll be corrected at the next update. Until then I'll just have to put up with the quirks.