US Copyright laws are good for 75 Years. This means almost all games are copyrighted.
However, there are some legal ways to aquire ROMs, and play older arcade games.
1) You can download Gridlee, Poly Play, and Robby Roto from
www.mame.net/downmisc.html. Howard Delman and Jamie Fenton released Gridlee and Robby Roto to the public. Poly Play is freeware because the former East German Government collapsed.
2) You can buy the Capcom Coin-Op Classics CD-ROM from Hanaho Games at
www.hanaho.com. This CD includes MAME32, and 14 legally licensed ROMs from Capcom.
3) Buy an ArcadePC Cabinet from Capcom, and you get 50 Capcom Arcade ROMs, plus MAME.
4) You can buy a real arcade board, and a ROM dumper device and dump the ROMs yourself.
5) You can contact the game companies directly and request to buy a license for the ROMs. The older and the less popular the game was, the more likely they are to do this for you. Also, the game companies vary. For example, Nintendo thinks that all emulation is illegal. However, if that were true, Capcom is doing a crime by licensing its ROMs through Hanaho, and Jamie Fenton making Robby Roto freeware. It is "fair game" with any game company on this issue.
NON-MAME Options:
1) Shockwave.com offers emulated versions of Root Beer Tapper, Satan's Hollow, Joust, Spy Hunter, Bubbles, and a couple other Midway games that play in your web browser. See
www.shockwave.com for details.
2) Return of the Arcade from Microsoft. This offers PC Ports of several classic arcade titles. See
www.microsoft.com3) Atari's Greatest Hits from Hasbro. This CD-ROM offers emulated versions of several classic Atari Titles.
4) Internet Gateway Inc offers Shockwave and Java based arcade and shareware clones of arcade games that play in your browser at
www.igateway.net.