I have two websites, the domain name is very similar (one hyphen difference), the new site is two months age with PR5 (but not yet indexed by Google), the old site is two years age with PR5 as well. In this case, should I do a 301 redirect o redirect the old site to the new site? or will it be better if keep the old site (surely I will change the content of old site to avoid duplicate content) and create some links pointing to the old site, thus will able to increase the backlinks of the old site? which way could get my old site indexed by Google faster? Appreciate some advice.
Your question is a bit confusing. Whatever you do, speed of indexing is not at issue. If you 301 one site to the other then the "values" of the 301'd site will transfer so long as the 301 and site remain in place. If you totally change the content of 1 site, as long as it is the same genre, you can create value by linking it to the other as long as you're not overly crosslinking. You'll just have 2 sites to market instead of 1. Dave
If I understand your question correctly, you are basically asking if it is better to keep the new site and redirect requests from the old site or is it better to keep the old site and redirect requests from the new site. An older more established domain with a good track record tends to be more valuable than a new domain name so I would probably keep the old site and redirect requests to it from the new site.