When using Opera with WordPress 2.1, the link to the Press It! bookmarklet does not appear on the Write Post page. Copying the link from a Firefox window into Opera's bookmarks demonstrates that the bookmarklet code does work in Opera 9. (I have not tested the current bookmarklet with older versions.)
It looks like you're doing excessive browser sniffing in post-new.php, assuming (incorrectly) that Opera cannot handle the feature:
if ($is_NS4 || $is_gecko) {
...
} else if ($is_winIE) {
...
}
Since WebKit?, Gecko, and Opera all work with the same JavaScript?, perhaps a better way would be something like this:
if ($is_winIE) {
...
} else {
...
}
Note for browser sniffing purposes: Beginning with Opera 9, Opera uses its own user-agent by default instead of spoofing MSIE or Mozilla. Neither $is_winIE nor $is_NS4 nor $is_gecko will fire. Example:
Opera/9.10 (X11; Linux i686; U; en)
