These are very finicky and very suspeptable to noise. In my opinion, not worth the headache over an Xbee. But if you really want to make use of these, you must do these two things:
1. Tune your antenna to the proper length. You can use this site to calculate a suitable length depending on frequency. (http://www.csgnetwork.com/freqwavelengthcalc.html). Full wave is most optimal, but 1/2 or 1/4 is next best. You can experiment by adding/trimming length to the antennas. This will reduce your SWR. (http://en.wikipedia.org/wiki/Standing_wave_ratio)
2. Packetize your data and use checksums. On the receiving end, compute the checksum to make sure the data is clean before you "trust" it.
The device appears to do some adaptation, so if you send 10-15 "warm up" characters before the "real" data, this appears to improve the chances of the real data to be clean.
I get about 1200-1800 baud of usable data when using 4800 baud input at 40 feet indoors.

I had difficulty getting correct/accurate data out of this chip. I stumbled upon this site and found it EXTREMELY useful. Now, 100% accurate data. I hated this transmitter until I found this site. Its for PICAXE but can be adapted
http://quicktrip.co.nz/jaqblog/index.php?option=com_idoblog&task=viewpost&id=25&Itemid=8

Maybe the same problem, but I don't know which side might have the problem, and I was just trying to see it using an LED - but does this have ANY drive capability? The datasheet says 10 microamps for both states.
The problem seems to be ASK or OOK, but it isn't quite that. If I keep the transmitter constantly on, I will only get a short pulse out of the receiver (if that). I would expect a switch on the transmitter would turn on and off something on the receiver 1-for-1 up to 4800 baud, but down to DC. Reading the info, there seems to be a requirement for some (unknown) switching of the data, i.e. a minimum frequency.

Sad that these still aren't back yet. Bummer that I only got two of these before they disappeared.
Could you guys source a module that can at least receive in the 315 MHz range so I can make use of the transmitters that are still available? I know there was a transceiver module that supported 433 MHz, 868 MHz and 915 MHz [ http://www.sparkfun.com/products/10153 ]. Be nice to have one at 315 MHz too.

DEPRECATED?? Noooooo these are so wonderful!

ETA?

OMG!!! NO!! why are they retired, i need these lol ... how much longer until they are back into stock .................WHY is this happening to me lol

VirtualWire for Arduino turns these things into the easiest thing in the world to use! They're not fast but they work great for home automation type projects and even some basic robot control.

Is this transmitter and receiver pair FCC certified? I read in another section that it is but I want to be sure before I use it.
If it is, does FCC give you a certificate saying it is ok to use this for hobby projects?
Thanks.

I got this working on a pair of Arduinos using the VirtualWire library. The PDF documentation for VirtualWire includes a very basic "hello" transmitter and reciever.
This thread was useful:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1208473338

I had some great frustration followed by great joy when I finally got these to work. It was thanks to this post on the Arduino forum:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1243851975
In case it helps anyone!

I had started with an antenna length of 13" and couldn't get it to receive. I then cut it back to 6" and was able to receive about 40' away with 3.3V transmitter supply.

Hi guys,
This one along with the matched xmitter are not working for me :( I am using two Arduino boards to interface to them but cannot seem to receive anything. I followed every tutorial out there and nothing :( Please let me know if you had similar issues. If you got them to work and you have a hint please let me know also.
Thanks.