Sorry I haven't had any experience with your mentioned transmitter/receiver but I have used a TWS-434A 434MHz RF Transmitter Module and an RWS-434 434MHz RF Receiver Module. I purchased them from Reynolds Electronics (http://www.rentron.com/). They were less than $9 USD apeice. Make sure you use some sort of encoding scheme such as Manchester encoding. I tried to use the output of the UART from an AT89C2051 to drive the transmitter directly and found that it wasn't very reliable. I read the following article in this post http://www.8052.com/forum/read.phtml?id=38804 and used that article to create my encode/decode routines. As soon as I implemented the manchester encoding the RF modules worked very well.

Kim Mansfield