If you want to change the default blue color of a selected cell in a UITableView do this:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
    
    // Configure the cell...
    cell.textLabel.text = [self.data objectAtIndex:indexPath.row];
    
    // change background color of selected cell
    UIView *bgColorView = [[UIView alloc] init];
    [bgColorView setBackgroundColor:[UIColor redColor]];
    [cell setSelectedBackgroundView:bgColorView];
    
    return cell;
}

Links that help:

http://stackoverflow.com/questions/1998775/uitableview-cell-selected-color