Yes, there are a lot of picture sharing sites for this. Since 900MB is a lot, he'd have to pay for it if he used Flickr or SmugMug. PicasaWeb is free though even for that much storage. They have a free client that he can use to edit and post the photos. Then people can download the full quality version.
A lot of professional photographers who do this and want to sell high-quality prints along with mugs or tshirts use SmugMug. It's around $12 a month, and allows users to store full RAW uncompressed versions online, and has other great features too.