Was thinking of visiting Russia, do I need a local guide or something like that?
Would be better if you did, maybe an organised tour with a guide. Otherwise you will need to speak some Russian, and know the Cyrillic alphabet.
You need a visa, which is expensive. I know that when cruise ships land in St. Petersburg, people can either apply ahead for a visa, or they can sign up for a guided tour, and then the visa is taken care of for them. Look on the consulate website for instructions on how to apply for a visa. As far as I know, you are not legally required to have a guide, but you may find it easier with one.
What you MAY need is an "AK-47", - and PLENTY of MAGAZINES, of AMMUNITION, - to PROTECT yourself!