C Sharp :: Write Log Using Static Function?

In my code, I wanted to write log exception to some file.

So I created a Utility class & wrote a static method in that to write log message to file.

public static void WriteLog(string message) {
  using (FileStream fs = new FileStream(@"c:log.txt",  FileMode.Append)) {
     using (StreamWriter streamWriter = new StreamWriter(fs)) {
          streamWriter.WriteLine(message);
     }
  }
}  

This works fine so far but I fear if two methods call this function simultaneously.. what will happen? Also, I want to access this same Utility library in my other "WEB" projects... will it work there too?Or else.. what will be the best way to log exceptions in any project?