1. add a note to the header for admins if there are any spam posts. It should only appear when there is spam to deal with. (make it a link, then we can jump straight to the spam page).

2. move the administer spam posts from Administration » Extensions » Manage Extensions to a new page - I'd suggest a new page within the Management section

3. instead of my previous fix, have a new option that sets how long the ban should last, possibly a drop down that has set options:
days: 1, 7, 14
months: 1,3,6
years:1,2
and never (default).

4. add a mark as spam to the post-actions section for each post.

I can't remember now, sadly.

I've made a few small modifications to the extension, but they might not suit everyone. This was because an old 1.2 forum was getting hit by spam, and the modification for that was setting expire to NULL. After 4000 bans I can't get the bans page to load.

To avoid this issue with this extension I changed Line 81 of manifest.xml from

$ban_expire = 'NULL';

to

$ban_expire = mktime(0, 0, 0, date('m')+1, date('d'), date('Y'));

which will hopefully work - it hasn't caught any spam so far on a 1.3 forum!

Bug - your php checking is good, but I had a problem on my host where php 4 & 5 are available but 4 is active by default. I fixed it by changing it to 5 but it might be a problem for some.

Warning: include(../extensions/akismet/lang/English/akismet.php) [function.include]: failed to open stream: No such file or directory in /var/www/vhosts/---.net/httpdocs/discuss/admin/extensions.php(664) : eval()'d code on line 246

Warning: include(../extensions/akismet/lang/English/akismet.php) [function.include]: failed to open stream: No such file or directory in /var/www/vhosts/---.net/httpdocs/discuss/admin/extensions.php(664) : eval()'d code on line 246

Warning: include() [function.include]: Failed opening '../extensions/akismet/lang/English/akismet.php' for inclusion (include_path='.:') in /var/www/vhosts/---.net/httpdocs/discuss/admin/extensions.php(664) : eval()'d code on line 246

Edit: now fixed

It's go to be something with your CSS files.

In IE 7 the little checkbox is properly visible. But still, the section isn't tagged as where the Akismet API key should go. Nor do I know what the checkbox is for.

Also looks like my screenshot in the latest versions of Opera and Safari.

It looks fine to me on both Firefox 3 and IE 7.