Any PHP function that can fetch remote URLs can help you with that. This can be as simple as doing
readfile('http://example.com'); // outputs contents of URL
If you need to scrape only some contents of a URL or want to postprocess the content, consider using DOM. In case you are trying to parse a specific XML format like RSS, use a parser specialized for that format. If there is no parser for that format, use XSLT to transform it to HTML.
As for database access, why not ask the owner of the remote site and database if and how you may access it.
Like the comments below your question already suggested, if you can be more specific about the problem, we can be more specific about a solution.