At your point of arrival in Russia you have the option of completing a customs declaration form, where you can list any foreign currency and valuables (including jewelry, cameras, laptops, mobile phones etc.) you are bringing into the country. This is no longer compulsory, but is advisable to avoid any problems on departure. Apart from the obvious list, the only things that you are not allowed to bring in to Russia are GPS devices.
Export controls are more rigorous, and ever-changing. You should declare if you are taking more than $3,000 out of the country, although this is only for 'statistical' reasons, and you are entitled to export up to $10,000 dollars. Works of art and antiques (which means anything made before 1960) have to be cleared by the Ministry of Culture, and may incur export levies of up to 100%. The same goes for books and, if you are planning to buy anything of the sort during your trip, we strongly recommend you insist that the vendor does the paperwork for you.