The most common way to time travel on the web is to visit that doyenne of web archeology The Wayback Machine. She kindly archives all those embarrassing early corporate websites, and no doubt a lot of work that has long since dropped off your cv. But what if you wanted to actually go time travelling?
A good place to start could be Chronos Technologies of Washington DC. Founded in 02105 they specialise in information to help you build your time machine. And they also have a gift shop. Alternatively you could give a lot of money to the Time Travel Fund who will pay someone from the future to come and get you.
If you prefer your time travelling from the past then you may enjoy the blog of 17th century London diarist Samuel Pepys. Still blogging after all these years. If blogs are so last year then you might like to follow TweetCapsule on Twitter who is currently time-twittering from the early 20th century. His coverage of the US election made for fascinating reading - Tafte won in case you missed it.