These links, which are in no particular order, open in separate tabs.
Malta Buses photo gallery by Keith Till and Marco Zammit. The largest and most comprehensive collection of Malta bus photos on the internet, including vehicles in the old route liveries.
Buses in Malta by the Huddersfield Passenger Transport Group has several photos of each bus as well as fleet details, and includes a large section of buses in the old green livery.
Malta & Gozo Bus & Coach is a large flickr site with photos uploaded by members.
Malta and Gozo Buses is a another photo-sharing site devoted to Malta.
Johann Tonna Photography - a large Flickr site majoring on the preservation and refurbishment of Maltese buses.
M A Penn's photo gallery by Mike Penn includes several galleries of Maltese buses.
Robert Collier Maltabus - flickr site including Maltese buses and also a fascinating collection of Maltese bus models made by Robert.
Buses Around the World by Stuart Bell is a huge site including some Maltese galleries.
Focus Transport is a very extensive transport site and blog, which includes some items on Malta.
Tims Tours Photo Gallery includes a Malta gallery.
Please let me know if you have a relevant website and would like a link adding above.
Maltese Public Transport since 1856 - a fascinating history, right up to the present day. See also the Vassallo Malta homepage which has links to the histories of the Gozo Ferry, the Barrakka Lift, and much more.
Malta & Gozo Route Buses by Alan Edwards has a wealth of interesting information, including tickets, bus maps, and much more. There is also a section on the railway (see below).
Transport Tickets from Malta by Paul Xuereb.
Forums / Discussion Groups
There are Yahoo and Google groups devoted to Maltese buses and coaches, both recommended for the serious enthusiast:
A members-only Yahoo group.
Maltese and Cypriot Transport Disseminations
A members-only Google group.
The Malta Railway
Malta Railway by Mac & Keith is a comprehensive photographic record of the railway remains by Keith Till and Mac Head.The Malta Railway by Alan Edwards features interesting photos of what remained as at 2002, with informative captions. It makes an interesting comparison with the more recent photos on Mac and Keith's site.
Walking the old Malta Railway is by Don Gaunt who walked the line in 1995. It includes plenty of photos and description, updated in 2006 following a further visit.
Transport Malta - Malta's transport authority dealing with such matters as highways, licensing, and public transport. The new larger authority replaced the ADT circa 2009 and has wider responsibilities, also dealing with aviation and maritime matters.
Halcrow Report - Reorganisation of Bus Services in Malta. A report commissioned by the ADT and completed in 2005. This is a large PDF file (7.7 Mb) of the final report including a supplement, published January 2006.