There are many online storage systems such as Dropbox which gives you 2gb free before you start paying. Dropbox (and similar sites) can also allow some access to others for sharing documents.
Virgin cable gives you some free data space as well, don't know about other web access providers.
You can upload unlimited pictures to photo sites. Flickr costs $25 (about £15) per year and you can mark them as private or 'family only' so you can choose who can see them. Pictures can include jpg scans of receipts and other important documents. A good way to archive your photos and you don't have to post or e-mail family photos because they can see and print them online.