Interesting that you want everything in remote control just like Japan's remote controlled home w/ remote controlled toliet

. I do not think there are wifi lawn sprinkler that you can use IP address. If you're expert in electronics, why don't you create one by modifying the X10 timer that are connected to X10 systems and crack open the timer in your lawn sprinkler system and find a way to merge it so it can be controlled by your PC at your fingertip. Since the technology for home lawn sprinkler are so new, It is not even yet impemented.
I personally have 7 station Rainbird automatic lawn sprinkler system. I know how system work. I can simply wire X10 WiFi timer to "manual" button to run sprinklers. Manual button would run entire system at pre-set time. All you have to do is to turn off sprinkler's ON set time and use Manual button to operate while 7 station sprinkler timer remain intact. I'm just a electronic hacker and love to hack it to get things working with other devices.
AS for Alertmaster and other wireless deaf alert system with pagers. They're sucky and crappy. It have slow response time too. In fact I've helped installed some wireless Alertmaster for my friend. They're pieces of crap!!. Company that makes them do not understand deafie's need and demands. They just want to make money out of ya, and give you a crap about battery issue especially the one that require unsolder and solder battery. Stupid of them!!. If you like BB battery, why don't you modify it to work with BB battery. BB battery are sooo darn expensive!! Last time I was at Nebraska Furniture Mart at electronic section. They do sell BB under Sprint. saw battery for it cost $50!!

Why don't you find bigger battery or connect batteries in parallel in order to provide more amperage but same voltage making your deafie pager last all day even next day
X10 system would be very nice to have everything controlled by PC. I would plan on buying it for my home because my home wiring system are so easy to configure due to it's design. I would love to check my home status while I'm away from home. Using Blackberry or any pda to control it be nice!!
Catty