You can do it several ways. I had an IR controlled fan at my condo and it worked nice with an IR remote. I learned the IR into a RC2000 Marantz and it worked fine. No X-10 required, but you had to point the remote at the fan. It was very nice but I haven't seen an IR controlled fan in a while.
You can use X-10 in a few ways on any fan. There are wall switches that are made for inductive loads. This is what you would want to use on anything with a motor if you were going to change the speed. The problem is you may get a hum from the fan motor if you lower the speed. You could use a standard X-10 dimming switch as long as you only used it for on and off controls and used the pull chain for speed (this is what I do). The best option would be to use a "relay" style switch. These are the type used for florescent lighting and high current applications. The advantage of these type switches is that they are a direct contact switch (just like a regular light switch). The only problem with them is that they will make a thud noise when turned on and off (the relay inside them). If you are not in a hurry and want to spend about twice as much on a switch, Smartlinc has just produced a Silent Relay switch. It should sell for around 100.00 or so. There are also in-line modules that you could choose from.
Regardless of the switch you choose, you will need an IR to X-10 converter. The IR543 or 4040 (same part, different number) is the cheapest and most commonly used device for doing this.
