There are many excellent pages about the Game of Life. I've tried here to pick out some that have large pattern collections you can experiment with. Most of these have further links to explore as well.
To see any pattern from these collections grow, copy it to the clipboard and paste it into Winlife32. All known pattern formats can be interpreted, including the various dialects of XLife (usually looks like an ASCII art representation of the pattern, interspersed with commands), RLE (random-looking strings of digits and letters), and ProLife (which can only be read from a file with the .PLF filetype).