http://www.starshipmodeler.biz/
is a good shop for scifi and mech, as well as the other two I linked.
Ok, heres a gundam history
Gundam is the name of a special prototype suit created by the Earth Federation to counter Zeon's Mobile Suits. 
The Earth Federation controlls earth and most of the Sides. Sides are clusters of space colonies, more or less countries.
Side 3 is Zeon, they start a Revolution to become autonomious from the Earth Federation. They drop a space colony, operation Britan, on earth, to hit Jabrau's the EFSF's main base, it misses and damages alot of the world, most specificly it breaks off part of australia, completly sinking it (Sidney included).
The gundam was made to stop zeon, there was only one made, and it, and it's pilot, were so successfull that they continued the Gundam project, including when the EFSF became corrupt (the enemy) and used Gundams against the heros of the series (See Zeta Gundam)
Zeon created the first Mobile suit. They were an evolution of mechs used to build the space colonies.
the series started with Mobile suit gundam. This started the UNIVERSAL CENTURY timeline. Included is Gundam Igloo
, MS Gundam
, 08th MS team
, 0080
, 0083
, Zeta
, Advance of Zeta
, ZZ
, Char's Counter Attack
, Gundam Unicorn
, Forumla F90
, Gundam F91
, Crossbone Gundam
, victory Gundam
, G-savior
.
The majority of these are good, they dont reuse plot lines, though, alot of them are older. Gundam Igloo is the latest thats not manga... its absolutley amazing, its 100% 3d and it is absolutley amazing, it starts at the beginning of the one year war, when the federation did not have mobile suits, and Zeon did.
Now, that being said, they made spin off series. Each series has the same kind of storyline, something taking from the origional in one shape of form, as well as a 'Char clone.' Char is the main villian of the classic gundam. Char Aznable, the Red Commet, Zeon's lead ace (though, I would argue otherwise) He wears a helm that covers his face.
G gundam, is the first. It is basicly dragon ball Z with robots, each nation sends a robot into a tourniment to see whos the best (stupidity) Most notable Mech from this suit is the Devil Gundam, and the most kitted is the Shining/God Gundam 
Then there was Gundam Wing. Wing is the best of the spin offs (not just me, its the majority speaking). It consisted of an evil orginization on earth, (a few of them, fighting between untill one wins)called OZ who are opressing the space colonies. The colonies develop 5 Gundams and send them to earth to do terrorist actions against OZ. Most kitted kit from this series is Wing Gundam Zero Custom 
(specificly, this is form the OVA Gundam wing, Endless Waltz, see it, it has great music)
There is another series I know not much about. Its called After War Gundam X, which is about a play off of of the origional gundam and 'operation britan' where dozens of colonies were droped leaving the world apoclyptic (see mad max, heh) 
After this, there is a series that is either loved or hated. Turn ∀Gundam (thats Turn A Gundam) It is an interesting premise. Earth has reverted back to the industrial age, where Bi planes are the most advanced weapons on earth. The moon is still colonised by 'spacenoids' who have mobile suits. They invade to take the earth back. The earthlings discover a burried relic, the Turn A Gundam, as well as some other suits (Zaku Is and IIs). It has some of the strangest designs of any series (the turn A has a mustache O.o. This series links ALL of the series together, that they are all the same time line (which reinforces what is said in gundam wing, endless walts 'History is locked in an endless waltz of peace, war, and revolution' (something like that).
There is the series Gundam Seed, which is rather new. It has three series in it's cannon, Gundam Seed, Gundam Seed Desitny, and Gundam Seed Stargazer (3 episodes actuially not that bad. This series is trife. Its their way of doing the origional series again, with better animation. There are more EXACT plot lines stolen from the universal century series then there are in a soap opera. Some are almost exact, just change the animation and voices (see kira and stellar\Camille and Four Murassame) (see corridinators\Cyber Newtypes) (etc etc etc) They kitted seed an insaine amount, the most notable ones would be the Freedom gundam (clearly a remake of the Wing Gundam Zero) 
Then there is 00. I will admit I havent seen it, but from the merchendicing, and what I have seen, it looks to me, like another seed 'lets make some cash' crap series.
And for those who dont believe my Signature... 