With the probable exception of the Express editions, the answer is YES. You can purchase a license to access the TFS. This enables you to install Team Explorer which will plug into Visual Studio. That gives VS users access to version control and work items but none of the other Team features (e.g., Profiling, Unit Tests, etc.).
For Eclipse you should check into
Teamprise which provides the capabilities mentioned about for Java developers.
As an aside, you can install Team Explorer on Windows boxes and even non-VS developers can gain access to TFS version control and work item tracking. A similar solution is offered for the Java planform by Teamprise.
Finally, for the 'web portal' question... Assuming you mean the Sharepoint Services-based Project Portals which are created for each team project, you don't need additional licenses. Non-TFS users can manage documents, view reports, etc. without additional licenses. If you plan to extend TFS and the project portal (or and other web interface) to allow, for example, bug entry via the web, you will need additional licenses. Apparently internal users need the standard CAL (which would also allow access to Team Explorer) and external users would be licensed through a connector license. Please review the licensing docs and/or talk with your MS-rep before taking this as the absolute truth.