Flickr offers tools for uploading images

If you don't like working through a web interface for handling your Flickr account then you can use the standalone applications they offer for uploading and working with images in your Flickr account. Easy to install and even easier to work with makes this an option for the most novice users.

Also, Flickr has a pretty cool WinXP Explorer plugin that lets you 'Send To Flickr' right from within Windows Explorer. Can't get much easier than that. (look at the bottom of the tools page for the download and how to install here)

Flickr Uploader:
http://www.flickr.com/tools/