Alerts & Reminders based on SMS content
I'd go with Tasker for this. Tasker can react on a lot of events, an incoming SMS being only one of the many. You can then have it parse the SMS text, and react on keywords. There're probably already som "profiles" out in the wild which you could adapt (just check with a Google Search), you also can find more details on SMS Notification Management - Tasker Wiki. This is probably the most flexible solution.

To sum up alternatives already mentioned in the comments:


GO SMS offers a filter feature, as Sparx mentioned
SMS-Filter can check the SMS body and display notifications (again from Sparx)