There are a set of ant tasks for Mercury that allow you to perform dependency management tasks, specify configuration (e.g. server credentials), modify/alter the ant path and write to the repository. See this blog for details.
There are also Maven tasks for ant, though they are not as fully featured. Maven is moving towards Mercury (particularly for Maven3) so it makes sense to use the Mercury tasks.
The following configuration reads the dependencies from the specified pom and populates the specified variable with the resultant path:
<path id="my.compile.path">
<deps>
<dependency name="groupId:artifactId:1.0::pom"
pom="${basedir}/artifactId-1.0.pom"/>
</deps>
</path>
You can also use the Mercury tasks to deploy to a Maven repository using an Ant build file:
<repo id="myRepository"
url="http://localhost:8081/nexus/content/groups/public">
<auth name="myUser" pass="myPassword"/>
</repo>
<write repoid="myRepository"
name="my.group.id:my-artifact-id:1.0"
file="${basedir}/target/my-artifact-id.jar"/>