This works for me with Maven. Remove the spaces after the protocol parts of the repository URLs.
Code:
<repositories>
<repository>
<id>com.springsource.repository.bundles.milestone</id>
<url>http ://repository.springsource.com/maven/bundles/milestone</url>
</repository>
<repository>
<id>com.springsource.repository.bundles.release</id>
<url>http ://repository.springsource.com/maven/bundles/release</url>
</repository>
<repository>
<id>com.springsource.repository.bundles.external</id>
<url>http ://repository.springsource.com/maven/bundles/external</url>
</repository>
</repositories>
<dependencies>
<dependency>
<groupId>org.springframework.integration</groupId>
<artifactId>org.springframework.integration</artifactId>
<version>1.0.0.M4</version>
</dependency>
</dependencies>