You are looking for some source of free portlets? I assure you that you are not going to get many. What's more, if you got some, you probably would not be able to deploy on your server. Most of the portal servers are not compatible to each other. You can not deploy IBM WebSphere portlets to Oracle Portal Server and so on. Most of the portal server and not fully compatible with JSR 168, the interoperability standard for portlets. Yes, You will think yourself lucky reaching to POST (Portlet Open Source Trading Site) website. But alas, you will not find many of portlets there. Anyway you can start with few portlets there and soon we hope to see more portlets.
Here is a list of Portlet Catalog for your server.
|POST (Portlet Open Source Trading Site) - JSR 168||http://portlet-opensrc.sourceforge.net/|
|IBM WebSphere Portal Catalog||http://www-306.ibm.com/software/genservers/portal/portlet/catalog/|
|Oracle Portal Catalog||http://portalcatalog.oracle.com/|
|BEA Weblogic Portal Catalog||http://dev2dev.bea.com/products/wlportal/psc/index.jsp|
|Jetspeed Portal Catalog||http://jakarta.apache.org/jetspeed/site/catalog.html|
Ofcourse you can find some more portlets on open source portal products like eXo and Liferay etc.. But the process is a tedious one. At present there seems no option other then to check your portal vendor.
The list is not any way complete. But I didn't get sufficient time to research on it. Please let me know about the missing resources. I'll include those in the list.
UPDATE Nov. 27, 2004: We have setup a free portlet repository from where many portlets can be downloaded. You can also upload your portlets there.