Here is the code for creating dll from CS file.
First put your cs file in C:\Program Files\Microsoft Visual Studio 8\VC
And choose Dot Net command prompt as follows,
All Programs ->
Microsoft Visual Studio 2005 ->
Visual Studio 2005 Command Prompt
Enter the following and press enter key,
csc /t:library /r:System.Web.Services.dll /r:System.Xml.dll myClass.cs
t --> means Target
r --> means Reference.
System.Web.Services.dll is webservice's reference.
System.Xml.dll is XML's reference.