Ok, here is how to do it, quick and dirty without the help of any special tools or resources:
1. Google for "ping blog" (yes, it doesn't matter if your site is a blog, any crawlable URL is fine)
2. Ping the URL via the services you find, just try to avoid pinging the same services multiple times. The crawlers of all big search engines, including Yahoo, will arrive within a minute after the pings. Again, the spider will come, no matter if it's a blog, if it has a feed or not. Check your logs, it's almost instant.
3. Create an account at
http://myweb.yahoo.com/, it's Yahoo's own social bookmarking service, and add the link there.
4. If you added links to your new site on other sites, ping these URLs with your link on them as well, so the spiders find the links quicker. Keep in mind, not too many links at once, just a few.
This doesn't guarantee you'll show up in Yahoo within 24h, but it's an easy and pretty effective way that works most of the time.