do some searches in google for them. Do some searches like: "your niche" + blogspot.com "your niche" + wordpress.com etc. You can also search your niche on google blog search and wordpress blog search.
Web 2.0 is also a great way to get your site noticed. Helps in driving traffic to blog. Web 2.0 is basically writing articles and posting it randomly on your blogs. web2.0 blogs are available online , you can search them on google. Or else you can try vmoptions.