"It is 1:01 now."
In this sentence? Very informally, 「一時一分だ、今」 (where だ is the informal version of です).
In other sentences, you can usually move it around fairly easily without affecting the meaning too much, but time clauses are typically put at the start.
・今、ジョンはバスでごはんを食べています = "Now, John is eating rice on the bus"
・ジョンは、今バスでごはんを食べています = "John is eating rice on the bus now"
・ジョンはバスで、今ごはんを食べています = "John is now eating rice on the bus"
・ジョンはバスでごはんを、今食べています = "John is now eating rice on the bus"
I just went and edited my examples by bolding the はs in them (They were there the whole time though ;) )
In this sentence, は is not strictly necessary to convey meaning, especially if you have a more important topic than the time clause (今) such as ジョン in my examples, though I believe it is more grammatically correct. It is very often left out after time clauses in speech and casual communication.
いまは is there because the sentence specifically says "now" in it. I think though just like in English, you can leave it or get rid of it and still convey the same meaning. [It's 1:01 now] vs [It's 1:01]. I think it boils down to the context of the conversation. [What time is it right now? It is 1:01 now.] vs [What time is it? It's 1:01.] The sentences are structured differently but the message is the same.
分 by itself is pronounced ふん ("fun" in rōmaji), although the Japanese F is NOT pronounced like in English. In English, you use your teeth and your bottom lip, while in Japanese, you don't use any teeth, just blowing air while trying to close your mouth. Imagine it like blowing out a candle.
If you know IPA, the English F is /f/, while the Japanese is /ɸ/.
However, 一分 is not pronounced いちふん. Instead, it's いっぷん, because people decided it was easier to pronounce that way.