No obvious robust solution for those users who use TeX rather than LaTeX. You will have to go to the http://xxx.lanl.gov/hypertex page and start digging in the macro section. Like hyperbasics.tex a TeX macro package referred to at this site. When we are convinced that it works in a straighforward manner we can install it.
The \special commands have been adopted as defacto standard, and you can in principle make macros based on them that will run without invoking any further packages. Many people have also written packages that take care of crossreferencing for you using these commands as a base. The most generally accepted package however, is the hyperref LaTeX package.
It looks superficially easy to write macros yourself using these \special commands
and indeed many external URL's are very simple to call. However references within
a document uses the '#' chacter which is also special in TeX and this
causes difficulties. This extends to other characters such as
'@' and '~'. If you use LaTeX, it is clearly easier to use
hyperref package unless you really know what you are doing.
The TeX programmer who writes his own macros must solve this though since
hyperref is for LaTeX.