This should do the trick:
VB
vbc /imports:System,System.Data,System.Data.SqlClient,System.Xml,System.Collections,Microsoft.VisualBasic,System.Security.Permissions,System.Reflection,System.Runtime.InteropServices /t:library /r:System.Data.dll,System.dll,System.Xml.dll /out:SqlHelper.dll *.vb
C#
csc /t:library /r:System.Data.dll,System.dll,System.Xml.dll /out:SqlHelper.dll *.cs