This is a fun and relatively easy thing to do, and is getting more and more popular these days. First, decide what type of information you want to share on your website. Everything to do with the engagement, i.e, how the proposal happened, pictures of the ring, pictures of happy smiles, how you both felt, etc.? Do you want to make frequent updates with posts about your dress shopping experiences, flower confusion, caterer choices, etc? Do you want to invite suggestions, advice, or create polls? Or do you want to make it simply a site that announces your engagement, with updates to dates and such?
There really is no end to how you customize your wedding website. Some couples even keep it going long after the ceremony is over, and add honeymoon pictures and stories, pregnancy announcements, anniversary etc. And family and friends will of course love to visit your site to see pictures of bridal showers, the Wedding Day pictures, Reception pictures, etc.
You can start your own site from scratch if you are HTML literate and computer-savvy, or if you are like me and not so much computer savvy, you can use a site such as ewedding.com and start setting up a website right away!
Have fun, be creative, and enjoy sharing your wedding excitement with friends and family!