According to a website I saw yesterday, Goloka, the abode of Krishna is said to be mentioned in the Srimad Devi Bhagavatam. Is it really present? If yes, what does the Srimad Devi Bhagavatam say about it?
Yes, there are many references in the Devi Bhagavatam to Goloka, most of them in the 9th Skandha. Here is what the first chapter of the 9th Skandha says:
This (Highest) Prakriti is recognised as five-fold. When She is engaged in the work of Creation, She appears as :-- (1) Durgâ, the Mother of Ganes’a, (2) Râdhâ, (3) Laksmî, (4) Sarasvatî and (5) Sâvitrî.... Now I will describe to you about the Fifth S’akti, the Devî Râdhikâ. Hear. She is the Presiding Deity of the five Prânas; She Herself is the Life of all; dearer than life even to S’rî Krisna; and She is highly more beautiful and superior to all the other Prakriti Devîs. She dwells in everything; She is very proud of Her good fortune (Saubhâgyam); Her glory is infinite; and She is the wife, the left body, as it were, of S’rî Krisna and She is not in any way inferior to Him, either in quality or in the Tejas (Fiery Spirit) or in any other thing. She is higher than the Highest; the Essence of all, infinitely superior, the First of all, Eternal, of the nature of the Highest Bliss, fortunate, highly respected, and worshipped by all. She is, the Presiding Devî of the Râsa Lîlâ of S’rî Krisna. From Her has sprung the Râsa mandalam and She is the Grace and the Ornament of the Râsa mandalam (the dance in a circle in Râsa). She is the Lady of the Râsa Lîlâ, the Foremost of the Jovial, humourous (witty) persons and dwells always in Râsa. Her abode is in Goloka and from Her have come out all the Gopîkâs. Râsa – the circular dance of Krisna and the cow-herdesses of Vrindâvana. Her nature is the Highest Bliss, the Highest Contentment, and Excessive Joy; She transcends the three Sattva, Rajo and Tamo Gunas and is Nirâkâra (without any particular form); but She dwells everywhere but unconnected with any. She is the soul of all. She is without any effort to do anything and void of Ahamkâra. She assumes forms only to show Her favour to Her Bhaktas. The intelligent learned men (Pundits) read Her Mahimâ (glories) in meditating on Her according to the Vedas. The chief of the Devas and the Munis could never see Her; Her clothings are fire-proof and She is decorated with many ornaments all over Her body. Her body looks as if the crores of moons have risen all at once; She is the Giver of Bhakti (devotion) towards Krisna, services towards Krisna; and She bestows all wealth and prosperity. In Varâha Kalpa, i.e., when the Varâha incarnation took place, She incarnated Herself as the daughter of one Gopa (cow-herd), named Vrisabhânu. And Earth was blessed by the touch of Her feet. She is such as Brahmâ and the other Devas could never perceive Her by any of their senses, yet everyone at Vrindâvan saw Her very easily. She is the Gem amongst women. And when She is seen on the breast of Krisna, it seems that lightnings flash in the blue mass of clouds in the sky. In days gone by, Brahmâ practised several austerities for sixty thousand years to purify Himself by seeing the nails of Her toe; but far from seeing that, He could not have that even in his dreams. At last He succeeded in seeing Her at Vrindâvana and became blessed. O Child Nârada! This is the fifth Prakriti and She is denominated as Râdhâ. Every female in every Universe is sprung from a part of S’rî Râdhâ or part of a part. O Nârada! Thus I have described to you the five Highest Prakritis, Durgâ and others. Now I am going to describe those that are parts of these Prakritis. Hear. The Ganges, Gangâ has sprung from the lotus feet of Visnu; Her form is fluid-like; She is eternal. And She is the veritable burning fire to burn away the sins of the sinners. She is sweet to touch in taking baths and in drinking; She gives final liberation to the Jîvas, and leads easily to the Goloka abode.
You can see more references to Goloka in other chapters of the 9th Skandha. In any case, it's not surprising that the Devi Bhagavatam places such importance on Radha and Krishna in Goloka, as Radha-Krishna worship was popular among medieval Shaktas. That was the milieu in which Chaitanya Mahaprabhu was born.