Looks like you have Maven configured to access only the JBoss repository. You'll have to change to change that to also use Maven Central - that's where thisarchetype is located.
(The JBoss repo has a snapshot for version 5, version 1.0 would come from Maven Central)
I have found two repositories where download the archetypes:
Also I have found a searcher of archetypes (http://search.maven.org/), and if I search "maven-archetype-webapp" I found this archetype with information for pom. Which is the utility of this information if I have the archetype?
Thanks a lot.
Maven Central is located at http://repo1.maven.org/maven2 (that is the repo that was searched via http://search.maven.org). That's the repository you want to use (it is the deault if you don't specific a repository). If you set the JBoss repo in your settings.xml file, you need to also include the Maven Central repo. See the Maven docs: http://maven.apache.org/settings.html#Repositories