Where can I get free web hosting online?

Only one I know of: http://www.000webhost.com/

Google App Engine for Python and Java hosting.

Google Sites is nice with web-based HTML editor.

110mb

x10Hosting: Probably the most reliable PHP host, though you won’t know reliability until you’ve tried a good paid host.

Dropbox Yes, another creative use of Dropbox. Make a subfolder in your public folder, and you instantly have a site with a url like http://dl.dropbox.com/u/000000/mysite/index.html.

Finally, some great inexpensive paid hosting if you decide you’re somewhat serious about web designing or programming:

Media Temple $95 Gift Card: Buy it for yourself to get a full year of probably the best hosting in the US. Great deal—been using it for 2 years.

Dreamhost: Also reliable and cheap. Great deals on VPS hosting.

The one i know that is very usefull and supports php is :
http://www.brinkster.com

@Alireza The free package is difficult to find on Brinkster, so here’s the link. Note that there are some nasty limitations on the free plan, such as a 16.7MB – 66MB traffic limit, file type restrictions, and a required subdomain.brinkster.net URL.

Here is a list for you to choose from.

Free web hosting is not safe as paid one, and many features are disabled for them.
just a suggestion