There are downloads for Solaris, Linux, HP-UX, IRIX and Windows.
Binary releases are much easier to install than source releases.
To find out whether a binary release is available for your platform, check the Ajuba Solutions Tcl Resource Center . Also, check in the FTP directory from which you retrieved the base distribution. Make sure you have the most recent patch release. Look in the FTP directory from which you retrieved this distribution to see if it has been updated with patches. Patch releases fix bugs, so you should normally use the latest patch release for the version of Tcl that you want.