...as long as you have wireless broadband that is!
If you're still talking about the 5800 I would be astonished if it didn't. I had a quick look at the nokia website and it said that only the 3G version of the phone had wifi... My N96 hooks up to my orange broadband with no problems at all, and I'm pretty sure that the N96 and the 5800 are based on the same technology.