The standard 9 pin serial port is near and dear to all of our hearts due to its ease of use for controlling external devices. Unfortunately, many “modern” laptops and some new computers lack a serial port. Fortunately there are a variety of USB to Serial converters available on the market. However, not all of these are created equally! In order to work with the PicAXE family of microprocessors, the converter must support the USB break command. Converters based on the Prolific chipset do this, while ones based on the Cypress chipset do not. I had purchased one based on the Prolific chipset from Peter Anderson some time ago and it worked great. Now I have found a new source of the prolific based converters that is selling them on EBAY for just $6.99 delivered! http://stores.ebay.com/Superdeal-01
I am not connected with this vendor in any way, just very happy with the product.
I am including a picture to help you identify them. I have tested it with several different PicAXE chips and it worked flawlessly.