Be careful guys, the exploit used by the new jailbreak makes it possible for malicious and possibly dangerous code to be injected into your device via a website. (The same way that the jailbreak itself was.)
The jailbreak uses an exploit in Adobe’s PDF software on iOS, making it possible to write data to the OS through a web browser. Of course, exploits like this aren’t new, and shouldn’t deter you from using your device normally. The difference is the amount of publicity this specific vulnerability is getting.
Another thing to note is that it isnt limited to PDF files: thats just how JailbreakMe is implemented. It could happen in elsewhere.
You should know that there are /lots/ of public exploits out there, and @comex’s JailbreakMe just uses one of them. No big deal.
Just be careful what sites you visit, and install this patch. It will give you a prompt when a website tried to load a PDF; It’s not a complete fix, but it will help temporarily.