So far from what I have figured out, getting email notifications is one of the main reasons for having a BlackBerry.
Do you only want to use your 8130 as a phone? Email & data are generally plans you set-up with when you get your phone. You don't have to set-up an email account with your 8130 if you don't want to send and receive email from the message program on your 8130, but you could still send emails from the browser through the web. This would be a little inconvenient though and defeat the purpose of having a BlackBerry.
If you want to send messages from the device without going on the web, you should run the set-up wizard and enter the email addresses you want to send from. Then go to Sprint.BlackBerry.com (from a PC) which is the email set-up page I use and I am on a BIS account. You do have to set-up an account to access it but once you have, you can put filters on your email addresses you have on you BlackBerry. One of the filters is to not send email to your device and then you will only be sending email and not receiving it. By doing this you won't have to go to the web page to send messages, only to view new messages.
You can change the size of the text by clicking the Settings icon and going to screen/keyboard. Then you can change the font and font size.
You should be able to install AIM by opening your 8130's browser. It is one of the bookmarks under links. Just click install AIM and you will be good to go.
Let me know if you have any other questions.