Singleton pattern on the web

I would love some feed back so please don't hold back.

I have a webservice that is responsible for formatting tons of information that is then queried by other applications (agents) that utilize it (the info packets).

All this "formatting" and logic I am talking about needs to be done in a centralized place and accessed by the agents. That is why we chose to go with a web service. This formatting and logic also needs to be done and held in memory so the agents don't have to wait for it. So we decided to implement a sort of singleton pattern. What do you guys think?

   1:  public class PacketManager 

   2:  { 

   3:      private static object lockObject = new Object(); 

   4:      private const string CACHE_MANAGER = "Mngr:PacketManager"; 

   5:      private List<InfoPacket> _preparedPackets; 

   6:   

   7:      private PacketManager() { initFunction(); } 

   8:   

   9:      public static InfoPacket GetInfoPacket() { return Instance.getInfoPacket(); } 

  10:   

  11:      public InfoPacket getInfoPacket() { ......some code ..... return this._preparedPackets[0]; } 

  12:   

  13:      private static PacketManager Instance 

  14:      { 

  15:          get {

  16:              lock(lockObject){

  17:              

  18:                  PacketManager oManager;

  19:              

  20:                  object o = System.Web.HttpContext.Current.Application.Get(CACHE_MANAGER);

  21:                  if(o==null){

  22:                      oManager = new PacketManager();

  23:                      System.Web.HttpContext.Current.Application.Add(CACHE_MANAGER,oManager);

  24:                  } else oManager = (PacketManager)o;

  25:                  

  26:                  return oManager;                

  27:              }

  28:                  

  29:          }

  30:      }

  31:  } 

Here is more information on the Singleton Pattern: http://www.yoda.arachsys.com/csharp/singleton.html