From MSDN..... (Although text is reads VS 2005, applies to 2003 too) full article available at
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Set up remote debugging
To use remote debugging, you must add the appropriate user to the Debugger Users group on the remote computer. To do this, follow these steps:
On the remote computer, right-click My Computer, and then click Manage.
In the Computer Management list, expand System Tools, expand Local Users and Groups, and then expand Groups.
Double-click Debugger Users.
To add the appropriate user to the Debugger Users group, click Add in the Debugger Users Properties dialog box.
In the Select Users, Computers, or Groups dialog box, enter the appropriate user (for example Domain1\User1) in the Enter the object names to select field, and then click OK two times.
Close the Computer Management tool.
To set up and test remote debugging, follow these steps:
Use the local computer to build a Web solution on the remote computer, and then debug it. To do this, follow these steps:
Click Start, point to All Programs, and then point to Microsoft Visual Studio .NET or Microsoft Visual Studio 2005.
Click Microsoft Visual Studio .NET or Microsoft Visual Studio 2005.
On the File menu, point to New and then click Project.
In the New Project dialog box, click Visual Basic Projects under Project Types.
Note In Visual Studio 2005, click Visual Basic under Project Types.
Under Templates, click ASP.NET Web Application.
Enter a URL on the remote server for the location (for example,
Visual Studio .NET or Visual Studio 2005 creates the solution.
Open WebForm1.aspx in the designer.
Double-click the designer to open the Code Editor window.
You are in the Page_Load event.
Add the following code line to Page_Load:
Response.Write("This is a test")
While you are on this line, press F9 to set a breakpoint.
