Exporting your Tweets via PHP should be simple. There are several tools that exist but they are annoying and overly complicated. If you want to print your last 20 Tweets on your web page (like I did with the front page of blyon.com), you can now use my simple script.
The first hack at it failed quickly because Twitter actually rate limits how many times a single host can pull the XML data per-hour. To fix the rate limit issue I added a very basic cache function to the script which limits the requests to 60 an hour.
Setup and usage is simple, you include the PHP as you always would:
include("./twitter-1.0.php");
Configure the script by editing these items:
/* define where to store the cached result */ $CACHEDIR="/tmp/"; /* define your username */ $USERNAME="BarrettLyon"; /* define the max number of tweets to output */ $MAXTWEETS=20; /* error message when twitter fails */ $ERRORMSG="Awh... Twitter is broken/down/not working/unhappy...";
Then call twitterPrint() or just hack the script up to do what you want.
If you make changes or have improvement ideas, just comment on this posting and I will update the code.
Get the code here: twitter-1.1.php.

Thanks a lot!