@SrWebDeveloperOct 20.2010 — #Do you want to import a third party RSS newsfeed as content on your site, or do you wish to generate an RSS newsfeed your users may subscribe to?
Also let us know if you use a CMS and if so, which one.
@SrWebDeveloperOct 26.2010 — #yes i want use third party rss and i am not using any cms just using php and mysql[/quote]
One of the most popular recommendations for this kind of thing is the SimpleRSS class, discussed in depth here with example code and download link. It uses either CURL or file_get_contents to parse the URL, you have the option of specifying timeout and cache and results come back in a convenient associative array. You then format it as you see fit. Obect oriented, very stable and easy to use, all the basic features one would expect, easy to integrate into any custom site.
Or google search "php rss cache importer" for other choices if this one doesn't do what you want and you want more advanced features such as templating, crontab compatibility, export to numerous formats, built in social networking sharing, multi-site aggregation and so on. If you need recommendations on those, feel free to ask.