Welcome to the forum!
Now that you are over in the Linux world, there are some differences from the Windows world. Just like with anything, there will be a slight learning curve. Some basics include
http://en.opensuse.org/Concepts ,
http://www.novell.com/documentation/...103/index.html ,
http://en.opensuse.org/YaST , and
http://opensuse-community.org/Restricted_Formats/10.3 .
As for multimedia, depending on whether you are using KDE or GNOME, you will have some installed by default. With KDE, I use Amarok for audio, Kaffeine for video, and Real Player is in there, too. You will find the greatest success rate with using the packages already provided by the openSUSE DVD. Pretty much everything you need is already on there. You will need the restricted formats installed from Packman and VideoLan. Those links are above.
Always remember that Linux is NOT Windows. There are some applications you may have used previously that are not the best choices anymore. You may find
http://www.linuxappfinder.com/alternatives to be a good resource for you to become acquainted with the new programs over on this side.
As for adjusting the font size, if you are using KDE, you click on the K Menu > Favorites (by default settings) > Personal Settings > Appearance & Themes > Fonts. You can choose and configure sizes from there.
We are very glad you are using openSUSE. Please feel free to post any questions you may have. There will be some. Also, you can pretty much bet others have had the same problem previously, so you might want to search, as well. We all started exactly where you are right now, so we understand what you are and will go through. This is going to be a learning experience. It will be worth it! Good luck and have fun!