elFirekrakor

Hi,
My website was a bit outdated so I made a new Wordpress site that looks much more modern. I am about to upload, but need to know the correct way to handle my 'old' site, as it's been up for 2 years and the pages are ranked in the search engines. I'm thinking I should keep the old pages on the server for a while (how long?) and somehow make 'redirects' from the old pages to the new? Maybe I'm wrong?
If anyone can offer some guidance or direct me to a good tutorial.
Thanks!