Old administrator's name appears as user

You must still be in your late brother's account. In Sys Prefs > Accounts create a new account with your name and make sure it has Admin privileges and then log out of this account ( Log Out), and log into your newly created account.

In that new account set up your email again, and having done that you should not be prompted for a password after the first time it is remembered.

Using Migration Assistant when there already exists an account adds an account to the one already there. You say there is only one. Somehow you have added your data to your brother's old account.

One of the problems of taking over the use of someone else's computer, is twofold, basically you are trying to overlay your setup on someone elses, and second but often overlooked is the possibility that over the years that account may have had stuff added, deleted, modified, hacked and who know what over the past five years since Leopard has been around, so the system itself may have some tangled idiosyncrasies that are not yet apparent but may be future trouble yet to show.

You are reluctant to reinstall from scratch, thinking it a chore but it really may be the quickest and least troublesome method in the long run.

If you want to persist and just change the account you could try this procedure.

http://support.apple.com/kb/HT1428

If you want to reinstall and then use Migration Assistant to set up your account afresh, the details of using MA to its best are in this link.

http://support.apple.com/kb/HT4413

Hello Mary Lou,

Before I start, I assume that I should start up the newer iMac from its original start up disk. Is there an article which reviews this procedure?

This requires the 10.5 Leopard Installl disks. You will have two original grey disks. or one black retail DVD. Insert whichever media you have.

Start from the 10.5 Leopard Installl disk 1 as per this article,

http://support.apple.com/kb/HT1544

and choose Erase and Install.

After it has installed, further along you will be asked whether you want to migrate your data. If you do, you will need to connect the two computers. Connecting by Firewire cable is a good method, and select which things you want moved. It pays to click on the triangles in that dialogue box and peruse what is available. Just your old User account may be enough, plus your email setup.

what happens when an application I send over needs to be updated to accommodate the newer OS?

I prefer to reinstall third party applications manually by either copying the application's .dmg over later via a USB stick, or once on the internet download the latest version from the developer if one is available. Why? no reason really, I just prefer to first get the Mac OS itself in a good state, and then later add other people's software to it. You may find some software from Adobe can only reinstall from the CD.

Should I do any cleanup on the older iMac before sending data to the newer iMac?

There is no need for that, just bear in mind here is an opportunity to leave a lot of your old stuff behind which is no longer relevant or just like the proverbial pile of newspapers in the corner, leave that behind. Whether moving house or updating an OS, both present the opportunity to question what to keep and what to leave.

I would like to review ... erasing all data from newer iMac.

The erase and install will be sufficient for you. There are no security issues involved here, just a clean sweep that will remove all of your late brother's previous settings, allowing you to customise the account accordingly.

I hope things proceed well for you.

Yes, there are a couple of ways. Once Leopard is installed, from the new iMac's Mail appliccation you can choose File > Import Mailboxes, and navigate to the (still connected) old iMac where it will be in your old user account / Library / Mail.

At that location, you'll see your old Mail account, which will be a folder (it may start with POP) and have you email address in it. Choose the entire folder and this will be added to your new iMac Mail sidebar under 'On My Mac'.

Any other Mailboxes in that old iMac location can also be imported as well.

If your email account is not in home/Library/Mail folder I cannot guess where else it would be.

Other methods of connecting two Mac are via ethernet cable or wireless or copy the stuff over onto a USB stick. I profess no understanding of wireless so you will have to post that as a new question to someone else. If it was me and the project could fit on a USB stick i do it that method because it is simple.

Here is a link for iTunes 9

http://support.apple.com/kb/DL1056

Your old iTunes Library folder should be placed in the ~/Music folder