Is it possible to add picklist values (the metadata) using apex and a VF page?

I have a VF page that displays the lead source picklist values from the contact object on a VF page:

public List<SelectOption> getLeadSourceNames()
	{
  		List<SelectOption> options = new List<SelectOption>();
        
   		Schema.DescribeFieldResult fieldResult = Contact.LeadSource.getDescribe();
   		
   		List<Schema.PicklistEntry> ple = fieldResult.getPicklistValues();
        
   		for( Schema.PicklistEntry f : ple)
   		{
      		options.add(new SelectOption(f.getLabel(), f.getValue()));
   		}       
   		return options;
	}

On my VF page, I display the selectList and if the user select 'Other' it will open a text field where they can enter a new value and save.  It saves the value to the record, but doesn't add the new value to the actual picklist value metadata.  Is there a ay to do this?

Here is my VF page:

<apex:page standardController="Contact" extensions="DynamicPicklist" sidebar="false" >
	<apex:form >
		<apex:sectionHeader title="Dynamic Picklist" subtitle="Reusable code"/>
		<apex:pageblock >
			<apex:pageBlockSection title="Dynamic picklist" columns="1">      
				<apex:pageblocksectionItem >          
					<apex:outputlabel value="Lead Source" for="values" />          
					<apex:selectList value="{!leadSource}" size="1" id="values">              
						<apex:actionSupport event="onchange" reRender="newvalue" />              
						<apex:selectOptions value="{!leadSourceNames}"/>          
					</apex:selectList>      
				</apex:pageblocksectionItem>                                                  
				<apex:outputpanel id="newvalue">             
					<apex:outputpanel rendered="{!leadSource == 'Other'}">             
						<div style="position:relative;left:75px;">                               
							<apex:outputlabel value="New value" for="newval" />                  
							<apex:inputText value="{!newpicklistvalue}" id="newval"/>                  
							<apex:commandbutton action="{!saverec}" value="Add!"/>             
						</div>             
					</apex:outputpanel>          
				</apex:outputpanel>               
			</apex:pageblocksection>
		</apex:pageblock>
	</apex:form>
</apex:page>

Here is the saverec method:

public void saverec(){   
	con.LeadSource = newpicklistvalue;
	update con; 	
}

I would like to have the ability to add new picklist values from the VF page.  Is it possible using the metadata API?  If so, how?  I can't find any sample code that explains how to accomplish this.

Thanks for any help.