Using the API for this would be much easier and resource friendly. The API page is here -->> http://apiwiki.twitter.com/Twitter-REST-API-Method%3A-statuses-user_timeline
And this allows for 150 uses per hour. There is a separate count for authenticated usage of the API as well, so authenticated requests to the API are not included in this number. I addition, REST API POST requests are not counted on any limit.
Limits:
Authenticated 150 per Userid
Unauthenticated 150 per Ipaddress
POST Requests(such as update, direct message, etc) Unlimited.
If you need any help with this MaxEvans, I already have aliases for almost all of Twitters REST API.