Only script that is running on regular basis is script that outputs device ip and gps coordinates to my web server. That script is running in crontab and it is run every 15 minutes.

Same script gets the parameter file from my web server (via wget) and checks the file for a line for launching the web server. Other parameters can also be added to this file, e.g. a parameter for launching a somekind of scan sweep with all of N900 'senses' in case user cannot connect to it and launch them from web interface.

Web server is pretty dormant most of the time when there is no usage and I haven't seen (with my usage) anything difference whether the lighttpd web server is running on the background all the time, or not. I prefer to keep it running all the time.

I plan to add options for somekind of scan with all possibilities of N900. Also, with the ability to give custom commands directly from web interface, user can e.g. also use the abilities of phone-control script by MohammadAG (thanks for that btw, nice little tool ).