Is their a buttons avaiable for g mail or yahoo?

You can add buttons to your bookmark bar quite easily.

Right click on the bookmark bar (doesn't matter if empty or if on a button).
Select new bookmark.
A dialog box will open.
In the name box, type a name, such as Yahoo.
In the location box, type the URL, such as http://www.yahoo.com
Click Add.

Hope this helps.

There are a few solutions

There is a nice button addon for firefox:

https://addons.mozilla.org/en-US/firefox/addon/1320

Which is what I personally use

or there is

checkgmail in the repo:

http://www.ubuntugeek.com/gmail-notifier-for-your-ubuntu-desktop.html

Which sits in the system tray and will make noises when you get an email and can do any number of actions if you do

another option (if you use thunderbird (not webmail)) is to use alltray and stick thunderbird in the tray (as it doesnt usually have one). You can use alltray to put ANY app in the system tray (but not terminal or konsole for some reason)

Here's a really simple solution without installing any other apps or tools.

Browse the page (yahoo or gmail, etc.)

Grab the icon besides the address will probably look like a Y or a Email icon respecfully, and DRAG it onto the bookmark toolbar.

Now you can just start Firefox and click this icon directly to load your site(s). You can also right click on this field and select "Open all in tabs" to open all the bookmarks at once.