Thanks Johann, if it's of any help to others, here's what I settled on:

I made a file named pta-mode.py in my emacs directory, where I keep 
other lisp files, and put this in it:

;; This is basically a list of lists with a regular expression and
;; then the font name (or face name).  The numbers below refer to \\(
;; ... \\) constructs that mark what part of the re you want
;; highlighted
(defconst pta-font-lock-keywords
  '(
    ("- \\(ERROR\\) - \\w*\\(.*\\)" (1 font-lock-warning-face)
     (2 font-lock-comment-face))
    ("- \\(WARN\\)  - \\w*\\(.*\\)" (1 font-lock-type-face)
     (2 font-lock-comment-face))
    )
  "Expressions to highlight in PTA mode.")

(defun pta-mode ()
   (setq font-lock-defaults '(pta-font-lock-keywords))
)

Then I added this to my .emacs file to load this, and select it for use 
on all my *.log files (which suits my needs):

(autoload 'pta-mode "pta-mode" "PTA log mode." t)
(add-to-list 'auto-mode-alist '("\\.log$" . pta-mode))

On Thursday, May 22, 2003, at 02:11  PM, 
myrkraverk@users.sourceforge.net wrote:

> Hi,
>
> Matt Noel writes:
>> I want to setup a very simple mode for colorizing a log file.  All I
>> need to do is highlight any lines with the string ERROR on them.  I've
>> tried reading the documentation for font-lock but it's not clear how 
>> to
>> do this.
>>
>> Could someone point me to a simple example, or send one?
>
> Here is an example, it doesn't though specify how you use the mode on
> the log file.  Maybe you can edit it to suit your need.
>
> ;; This is basically a list of lists with a regular expression and
> ;; then the font name (or face name).  The numbers below refer to \\(
> ;; ... \\) constructs that mark what part of the re you want
> ;; highlighted
> (defconst masp-font-lock-keywords
>  '(("^\\(\\(\\sw\\|\\s_\\)+\\)\\>:?[ 
> \t]*\\(\\sw+\\(\\.[lLwWbBsS]\\)?\\)?"
>     (1 font-lock-function-name-face) (3 font-lock-keyword-face nil t))
>    ("^\\s +\\(\\(\\sw\\|\\s_\\)+\\(\\.[lLwWbBsS]\\)?\\)" 1 
> font-lock-keyword-face)
>    ("^\\(\\s-+\\|\\sw+:\\s-+\\)\\(\\\\[a-zA-Z0-9]+\\)"
>     (2 font-lock-constant-face))
>    ("\\(\\\\\\sw+\\)"
>     (1 font-lock-variable-name-face)))
>  "Additional expressions to highlight in Assembler mode.")
>
> (defun masp-mode ()
> ;;...
>   (setq font-lock-defaults '(masp-font-lock-keywords))
> ;;...
> )
>
>
> Hope this helps,
>
> Johann
>
> -- 
> This line is left blank intentionally
>
>