We recently reported on a pair of bugs in Android's Messaging app which handles incoming and outgoing SMS messages, and the fix released in updates to Gingerbread and Froyo. What was disturbing about these bugs was the amount of time that it took for Google to acknowledge the problems and develop a fix. (In their defense, it looks like Google did acknowledge the bugs and was working on a fix much earlier than we knew about -- because they didn't tell anyone.)
This bug isn't as bad as the last set (which could result in text messages being sent to an unintended recipient). This bug can result in text messages not being delivered when internal memory is "low". How low? According to the bug report: 8MB.
What's disheartening is that the bug was reported on November 22, 2009. Yes, 14 months ago. The work around is to make sure you haven't maxed out your internal storage, and if you notice you're not getting texts to uninstall some apps to free up space. Why getting a new text message would require more than 8MB free remains a mystery.
Text messages received by the Google Voice apparently are immune to this bug.