A little messy, but I tried my best.

Basic Numbers:
Arabic - Romaji, Hiragana、 Kanji
01 - ichi, いち、　一
02 - ni,　に、　二
03 - san,　さん,　三
04 - shi (yon), 　し　（よん）、　四
05 - go,　ご、　五
06 - roku,　ろく、　六
07 - shichi (nana),　しち　（なな）、　七
08 - hachi,　はち
09 - kyuu,　きゅう、　九
10 - jyuu,　じゅう、　十
11 - jyuu ichi, じゅういち、　十一
12 - jyuu ni,　じゅうに、　十二
13 - jyuu san,　じゅうさん、　十三
14 - jyuu yon,　じゅうよん、十四
15 - jyuu go,　じゅうご、　十五
16 - jyuu roku,　じゅうろく、　十六
17 - jyuu nana,　じゅうなな、　十七
18 - jyuu hachi,　じゅうはち、　十八
19 - jyuu kyuu,　じゅうきゅう、　十九
20 - ni jyuu,　にじゅう、　二十
100 - hyaku,　ひゃく、　百
1000 - sen,　せん、　千
10000 - man,　まん、　万

Days of the Week: All days of the week have one distinguishing kanji (the first one) and then the last two are all the same, and that is youbi.
Sunday: にちようび、　日曜日 (nichiyoubi)
Monday:　げつようび、月曜日 (getsuyoubi)
Tuesday:　かようび、　火曜日 (kayoubi)
Wednesday:　すいようび、　水曜日 (suiyoubi)
Thursday:　もくようび、　木曜日 (mokuyoubi)
Friday:　きんようび、　金曜日 (kinyoubi)
Saturday:　どようび、　土曜日 (doyoubi)

[ON a note: I really don't like romaji -.-;;; It's rather hard for me to read, I try to refrain from using it. I'll probably put them in quotes from now on if I feel that it may be necessary to use them. If words in English are in quotes, that is the definition or literal translation]

Months: Months are very self-explanatory. All you do is add the number and then attach the word for month (gatsu) after it. For months, this is perhaps one of the only times yon (4) and nana (7) are not appropriate. Asians make life easy by just calling the months by numbers + moon. So it's read as 1st Moon, 2nd Moon, 3rd Moon... 12th Moon. We call it First Month, Second Month, etc.　For September, the Japanese call it Ku gatsu rather than kyuu gatsu, because kyuu gatsu sounds really weird off the tongue, but jyuu stays as jyuu.
January: いちがつ、　一月
February:　にがつ、　二月
March:　さんがつ、　三月
April:　しがつ、　四月
May:　ごがつ、　五月
June:　ろくがつ、　六月
July:　しちがつ、　七月
August:　はちがつ、　八月
September:　くがつ、　九月
October: じゅうがつ、　十月
November:　じゅういちがつ、　十一月
December:　じゅうにがつ、　十二月

Days of the Month: This is something a lot of people find confusing, but it's not too bad. The first ten days are special, so they have their own ways of being called. After that, any number with the last digit as a 4 (i.e. day 14, day 24), will be called yokka -- do not be confused with youka (which is day 8). The days after the first ten have the ひらがな for nichi after it　(nichi is already within yokka). So for day thirteen, it will be jyuu san nichi. For the special days that end with the number four, nichi is not appropriate. The number 20 is special too and it's called Hatsuka, rather than nijyuunichi.
First Day: ついたち、　一日
Second Day:　ふつか、　二日
Third Day:　みっか、　三日
Fourth Day:　よっか、　四日
Fifth Day:　いつか、　五日
Sixth Day:　むいか、　六日
Seventh Day:　なのか、　七日
Eighth Day:　ようか、　八日
Ninth Day:　ここのか、　九日
Tenth Day:　とおか、　十日
Eleventh Day:　じゅういちにち、　十一日
Fourteenth Day:　じゅうよっか、　十四日
Twentieth Day:　はつか、　二十日
Twenty-Fourth Day: にじゅうよっか、　二十四日

(If you really need romaji for the ten days, I can go back and add them in). Anyhow, that's all for the moment.

~luvluv, Tsugi