You can check out WiiWare World's Space Invaders Get Even review if you're still undecided on a purchase and we'll have a full review of Pit Crew Panic up within the next day or so.
Until then you can take a look at the official Nintendo press releases for both titles below.
SPACE INVADERS GET EVEN (Taito, 1 player, Rated E10+ for Everyone 10 and Older-Cartoon Violence, 500 Wii Points): The Space Invaders are back, and this time they're out to get even. Take control of a UFO and make those Earthlings pay by unleashing your fleet of heroic invaders against their puny tanks, fighter jets and artillery-but watch out for the massive boss awaiting you at the end of each stage. Use your invaders' five attack types and the might of the mother ship to rack up high scores, then upload them via Nintendo® Wi-Fi Connection and see where you stand in the global rankings.
PIT CREW PANIC! (Hudson Entertainment, 1-4 players, Rated E for Everyone, 800 Wii Points): Pit Crew Panic! is a frantic, action-packed game that unfolds on the racing circuit. During the game, the pit crew is not only faced with repairing vehicles, but also various WHATSITs. Handling the WHATSIT repairs is a pit crew made up of legendary beauties. The controls are simple: Just grab a member of the crew with the Wii Remote™ controller's A Button, then release the button when the Pointer is over the damaged PART, and that crew member will begin repairs. Assign repairs to the members of your team and provide support using the Wii Remote to send a fully repaired WHATSIT out of the pit as quickly as you can. The game features Normal mode, which can be played using one of two rules: Abnormal mode (players split into two teams and compete against each other) and Ranking mode (compete with players around the world for the top record). Each mode can be played with a maximum of four Wii Remote controllers, allowing you to team up with friends and family. Your teamwork could lead to outstanding records.
And if for some reason these two WiiWare titles don't grab your attention, you can also check out the release of SNK's Neo Geo classic Metal Slug 2 on the US Virtual Console.