These are Wordpress 2.3 compatible plugins from letter I to L, these plugins can be downloaded from the sites specified below :

I - L

1. iG:Syntax Hiliter (http://blog.igeek.info/wp-plugins/igsyntax-hiliter/) 3.5
2. Import Users (http://www.dagondesign.com/articles/import-users-plugin-for-wordpress/) 1.1
3. Inline Ajax Comments (http://kashou.net/blog/inline-ajax-comments/) 0.3
4. Inline Ajax Page (http://anthologyoi.com/inap/) 2.4.6
5. InScript (http://urbangiraffe.com/plugins/inscript/) 1.7.3
6. In Series (http://remstate.com/projects/in-series/) 3.0.6+
7. Internal Rewrite Viewer (http://www.dagondesign.com/articles/wordpress-internal-rewrite-viewer-plugin/) 1.0
8. Intypo (http://dossier.dunker.de/intypo) (International Typography) 0.9.1
9. Interstitial Ads (http://www.dagondesign.com/articles/interstitial-ads-plugin-for-wordpress/) 1.0
10. JS AntiSpam (http://bueltge.de/wp-js-antispam-plugin/418/) 0.8
11. Jump To (http://urbangiraffe.com/plugins/jumpto/) 1.0
12. KB Advanced RSS Widget (http://adambrown.info/b/widgets/category/kb-advanced-rss/) 1.7
13. Kimili Flash Embed (http://kimili.com/plugins/kml_flashembed/wp/) 1.3.1
14. Language Translator (http://www.lancelhoff.com/2007/08/28/wordpress-language-translator-plugin/) 1.0
15. Last.Fm Records (http://wordpress.org/extend/plugins/lastfm-records/) 1.2.2
16. Latest Post from each Category (http://www.dagondesign.com/articles/latest-post-from-each-category-plugin-for-wordpress/) 1.7
17. Less (http://www.thunderguy.com/semicolon/wordpress/less-wordpress-plugin/) 1.1
18. Lightbox JS v2.03.3 Plugin (http://www.4mj.it/lightbox-js-v20-wordpress/) 1.7
19. Lighter Admin Drop Menus (http://www.italyisfalling.com/lighter-admin-drop-menus-wordpress-plugin) 2.3
20. Link Indication (http://sw-guide.de/wordpress/plugins/link-indication/) 3.2
21. List SubPages (http://www.dagondesign.com/articles/list-subpages-plugin-for-wordpress) 1.0
22. LiveJournal Crossposter 2.0 (http://ebroder.net/livejournal-crossposter)

You’ll find all infos about the plugins at the upper links.