That's just dumb, I should write it down somewhere. But then it's already written down. The real problem is that scrolling through your SMS history is a pain.
Introducing smurch, now available free on Google Play.
With smurch you can search through any SMS / MMS conversation. You never have to worry about pestering your brother for his buzzer code again. Acquaintances will be in equal parts pleased and creeped out that you remember where they live.
Smurch leverages texport's codebase, but instead of saving your conversation to a file (which you can then open in a web browser), it dumps the generated HTML to a webview, allowing you to easily search for any string occurrences.