I've noticed that MSN & Yahoo search will list your site in a few days, but Google takes like forever. Does this mean their webcrawl cycle is much longer?
No. They crawl all the time but new sites are sandboxed. It takes time, content and inbound links from trusted sites to come out. If you are in a competitive field it could be quite a while.
One of mine was indexed in about 48hours but then others still aren't picked up for about 2 weeks. One thing I have noticed if its a less full market e.g. hampsters with capes rather than pc's for example and you made tham both at the same time the hampster one would get indexed quicker.
You'd better submit a sitemap to Google.. I've a site launched 3 days ago and now it's already indexed by google
If you have couple of quality inbound links then 48 hours would be considered as enough time otherwise it can take more than 365 days
A good forum signature link can get a site indexed fast. Google and MSN usually pick it up real quick and Yahoo takes a little longer. Getting a site to start ranking is a different story.