Have a look at the following links, as the information presented there might be helpful in your future endeavours into Mac OS X and could clear up initial confusion and may even prevent harm to your system or your files.
Mac OS X Basics
About viruses and other threatening malware
Software for Mac OS X
Other useful links
Mac OS X Basics
Switch 101 - guide with articles made by Apple on how to accustom yourself, after you switched to Mac OS X from Windows
Mac 101 - How to get started with Mac OS X
Find out how - tutorial videos made by Apple on how to do certain thing in Mac OS X
Pro tips - tips made available by Apple for easier ways of doing certain tasks
Mac OS X Keyboard Shortcuts - Learn about common Mac OS X keyboard shortcuts.
Mac OS X Beginner's Guide by MacRumors - learn about software, media players, shortcuts and some useful tips, tricks and hints
Mac Guides - tutorials, product guides and more
About viruses and other threatening malware
There are currently, as of today, NO (ZERO) Mac OS X viruses in public circulation. That may change in the future, but for the last ten years Mac OS X has been void of viruses.
What is a (computer) virus: Wiki, HowStuffWorks.com, Department of Energy, Microsoft, AntiVirus Ware
What is (computer) malware: Wiki,
What is crime-ware: report by DHS
For further clarification on existing threats for Mac OS X and the differences between viruses, trojans, worms and other kinds of malware:
About file quarantine in Mac OS X v10.5 and v10.6 - files you download via Safari, iChat, or Mail are checked for safety when you open them
Software for Mac OS X
Other useful links