C# PriorityQueue<T> Implementation

Before I get any more abusive comments. This post is targeted at the 2.0 version of the Framework.

Guess I could of just used a SortedList<T1, T2> implementation in System.Collections.Generic, but I want a PriorityQueue<T>. So here goes.

public class PriorityQueue<T> : SortedList<T, T>
{
    public PriorityQueue()
        : base()
    {
    }

    public PriorityQueue(IComparer<T> comparer)
        : base(comparer)
    {
    }

    //
    // Summary:
    //     Returns the object at the beginning of the System.Collections.Generic.Queue<T>
    //     without removing it.
    //
    // Returns:
    //     The object at the beginning of the System.Collections.Generic.Queue<T>.
    //
    // Exceptions:
    //   System.InvalidOperationException:
    //     The System.Collections.Generic.Queue<T> is empty.
    public T Peek()
    {
        return this.Last().Key;
    }

    //
    // Summary:
    //     Removes and returns the object at the beginning of the System.Collections.Generic.Queue<T>.
    //
    // Returns:
    //     The object that is removed from the beginning of the System.Collections.Generic.Queue<T>.
    //
    // Exceptions:
    //   System.InvalidOperationException:
    //     The System.Collections.Generic.Queue<T> is empty.
    public T Dequeue()
    {
        T item = this.Last().Key;
        this.RemoveAt(this.Count - 1);
        return item;
    }

    //
    // Summary:
    //     Adds an object to the end of the System.Collections.Generic.Queue<T>.
    //
    // Parameters:
    //   item:
    //     The object to add to the System.Collections.Generic.Queue<T>. The value can
    //     be null for reference types.
    public void Enqueue(T item)
    {
        this.Add(item, item);
    }
}