Any text editor can edit Scheme, but some are better than others. Emacs is the best, of course, and not just because it is a fine text editor. Emacs has good support for Scheme out of the box, with sensible indentation rules, parenthesis-matching, syntax highlighting, and even a set of keybindings for structural editing, allowing navigation, cut-and-paste, and transposition operations that work on balanced S-expressions.
As good as it is, though, two things will vastly improve your experience with Emacs and Guile.
The first is Taylor Campbell’s Paredit. You should not code in any dialect of Lisp without Paredit. (They say that unopinionated writing is boring—hence this tone—but it’s the truth, regardless.) Paredit is the bee’s knees.
The second is
Antonio Ortega Ruiz’s
Geiser. Geiser complements Emacs’
scheme-mode with tight integration to running Guile processes via
comint-mode REPL buffer.
Of course there are keybindings to switch to the REPL, and a good REPL environment, but Geiser goes beyond that, providing:
See Geiser’s web page at http://www.nongnu.org/geiser/, for more information.