Dictionary serializable via XmlSerializer() http://weblogs.asp.net/pwelter34/archive/2006/05/03/444961.aspx

SerializableDictionary.cs

using System;
using System.Collections.Generic;
using System.Xml;
using System.Xml.Schema;
using System.Xml.Serialization;

[XmlRoot("dictionary")]
public class XmlSerializableDictionary<TKey, TValue> : Dictionary<TKey, TValue>, IXmlSerializable
{
    public XmlSchema GetSchema()
    {
        return null;
    }

    public void ReadXml(XmlReader reader)
    {
        var keySerializer = new XmlSerializer(typeof(TKey));
        var valueSerializer = new XmlSerializer(typeof(TValue));

        var wasEmpty = reader.IsEmptyElement;
        reader.Read();

        if (wasEmpty)
            return;

        while (reader.NodeType != XmlNodeType.EndElement)
        {
            reader.ReadStartElement("item");

            reader.ReadStartElement("key");
            var key = (TKey)keySerializer.Deserialize(reader);
            reader.ReadEndElement();

            reader.ReadStartElement("value");
            var value = (TValue)valueSerializer.Deserialize(reader);
            reader.ReadEndElement();

            Add(key, value);

            reader.ReadEndElement();
            reader.MoveToContent();
        }
        reader.ReadEndElement();
    }

    public void WriteXml(XmlWriter writer)
    {
        var keySerializer = new XmlSerializer(typeof(TKey));
        var valueSerializer = new XmlSerializer(typeof(TValue));

        foreach (var key in Keys)
        {
            writer.WriteStartElement("item");

            writer.WriteStartElement("key");
            keySerializer.Serialize(writer, key);
            writer.WriteEndElement();

            writer.WriteStartElement("value");
            var value = this[key];
            valueSerializer.Serialize(writer, value);
            writer.WriteEndElement();

            writer.WriteEndElement();
        }
    }
}