SharePoint 2010 drag & drop SPUser listbox items to SPGroup listbox, to move SPUsers to new SPGroup
===

I have 2 listboxes next to each other.
Left ListBox contains all the SharePoint Groups.
Right Listbox contains all the SharePoint Users. 

Listboxes are populated using C# and pulled using the following code

        SPSite currentSite = SPContext.Current.Site;

        foreach (SPGroup spGroup in currentSite.RootWeb.SiteGroups)
        {
             listboxGroups.Items.Add(spGroup.Name);
        }

        foreach (SPUser spUser in currentSite.RootWeb.SiteGroups[listboxGroups.SelectedValue].Users)
        {
             listboxUsers.Items.Add(spUser.Name);
        }

The selected value of the Groups ListBox is used to populate the Users ListBox. Basically, it shows the list of users in each group.

**Can someone tell me how I can move items (users) DRAG & DROP users from the Users ListBox control over to the Groups ListBox control. BUT, my intention is that, once a User item is released over a Group item in the Groups ListBox, then the user is removed from it's existing group and added to the new group over which it was dropped.**

I have the code for deleting a user from a group and adding them to another Group.

        public static void AddUserToGroup(string UserToBeAddedToGroup, string GroupOfNewUser)
        {
            SPWeb currentWeb = SPContext.Current.Web;
            SPUser userToBeAddedToGroup = currentWeb.EnsureUser(UserToBeAddedToGroup);
            if (userToBeAddedToGroup != null)
            {
                currentWeb.SiteGroups[GroupOfNewUser].AddUser(userToBeAddedToGroup);
            }
        }

        public static void RemoveUserFromGroup(string UserToBeRemovedFromGroup, string GroupOfUserToBeRemoved)
        {
            SPWeb currentWeb = SPContext.Current.Web;
            SPUser userToBeRemovedFromGroup = currentWeb.EnsureUser(UserToBeRemovedFromGroup);
            if (userToBeRemovedFromGroup != null)
            {
                currentWeb.SiteGroups[GroupOfUserToBeRemoved].RemoveUser(userToBeRemovedFromGroup);
            }
        }

If JQuery is needed to accomplish this, please can you show how to go about doing this. I do not know JQuery, and am new to JavaScript as well.

Thank you in advance.