Do you need to change your twitter password?
In case you have been living under a rock twitters DNS was comprimised (again) and some angry young hackers. (They should have used a better DNS managment system).
DNS is what changes your nice www.thanetstar.com into an IP address which can be used to get the web page from. Somehow someone managed to currupt this information and send all the traffic to another website.
The result was that for a short while twitter.com resolved to a server that was not owned by twitter.
Twitter itself was not compramised but should you change your password?
The answer is that it depends.
If you were not online during the DNS hijacking then you need to take no action. If you were online but were already logged in to twitter then you probably need to take no action. But if you sent your username and password to twitter but got the hijacked page instead then you must change your password because there is a chance that the hackers have ssaved that data.
There are better methods of authentication over the web than passwords but until such time as they are implimented in any useful way you had better just stick to coming up with realy good passwords ("password" is not a good password BTW).