The AN2295 boot loader supports the K60 so will be able to operate on your tower kit (maybe with a few adjustments for the UART needed and possibly the clocking).
You can also get serial loaders for the K60 tower kit from µTasker Test Software and Demos and sources from KINETIS Project Code which are configured for the kit and also have IAR 6/7 projects so that they work out-of-the-box. UART loading methods are SREC or KBOOT compatible protocol (KBOOT is probably the one to use for future Freescale compatibility) but you can also chose from Ethernet web server, USB-MSD, USB-HID (including KBOOT compatible mode) or SD card loading (or various capabilities in parallel). See also Re: Kinetis Boot Loader for SREC UART, SD Card and USB-MSD loading
