Action<List<ClubListing>> a = delegate(List<ClubListing> list)
        {
            for (int i = 0; i < list.Count; i++)
            {
                var cl = list[i];
                if (cl.MatchingClubListing == null)
                {
                    var compare = CompareNames(cl.Club.Name);
                    if (compare.Any(c => c.Value == 0 && c.Key.Club.State == cl.Club.State))
                    {
                        var match = compare.First(c => c.Value == 0 && c.Key.Club.State == cl.Club.State);
                        compareDialog.ClubA = cl.Club;
                        compareDialog.ClubB = match.Key.Club;
                        DialogResult dr = compareDialog.ShowDialog();
                        if (dr == DialogResult.Yes)
                        {
                            cl.MatchingClubListing = match.Key;
                            match.Key.MatchingClubListing = cl;
                        }
                        else if (dr == DialogResult.Abort)
                        {
                            break;
                        }
                    }
                }
                this.Invoke(new MethodInvoker(delegate()
                {
                    this.prbOperationProgress.Value = i;
                }));
            }
        };

        AsyncCallback callback = new AsyncCallback(SaveAndUpdate);
        var result = a.BeginInvoke(this.lbxLiveClubs.Items.Cast<ClubListing>().ToList(), callback, null);

Form parent = ...;
compareDialog.ShowDialog(parent);