Chances are, if you've looked into Sambo at all, you've noticed similarities between it and other arts.
Sambo (or SAMBO, the transliteration of САМБО, which itself is short for Самооборона Без Орыжия) is a hybrid martial art with roots in various forms of Folk Wrestling and Judo. As such, many of the techniques share similarities with those arts which derive from similar backgrounds (Brazilian Jiu-Jitsu, for instance, derives from Judo, which has its roots in jujutsu, a form from which aikido is also derived).
There is, of course, no substitute for training, and finding good training is about doing the leg work. That said, there are a number of different varieties of Sambo which you should be aware of, and knowing the differences can help you narrow down what kind of instruction you're looking for.
The Two I'm Familiar With
- Sport Sambo (борьба Самбо) – This form of Sambo is similar to Olympic Wrestling or Judo, with some leg locks permitted, and chokeholds disallowed. There are very few restrictions related to gripping or holding, and it emphasizes throwing, groundwork, and submission.
- Combat Sambo (Боевое Самбо) – Originally developed for the military, this is sport Sambo with fewer restrictions, and includes striking and grappling that would normally not be legal. In Combat Sambo competitions, there's an increase in protective gear as well.
Other's I Know Of
- Freestyle Sambo – A step less restrictive than Combat Sambo with some neck cranks and more leg locks allowed. This is an almost exclusively American form of Sambo.
- Special Sambo – A style of Combat Sambo specially geared toward use by special forces groups (ФСБ, ГРУ, etc.). It is not so much a unique style, but a subset designed and drilled to maximize efficiency in training special forces agents.
I have never seen anything of any quality on the internet. That said, if you're looking for media to get you headed in the right direction to pick a quality instructor, it's worth investing in good quality media. Budo Videos has an extensive collection of Sambo material, and generally the reviews have been pretty accurate.