The advent of Information Communications Technology has revolutionized ESL writing instruction. This quasi-experiment investigated the correlations of self-perception in reading, self-perception in writing, reading performance and writing performance of two groups of freshman college students representing two learning conditions -- the experimental group (38) exposed to Web-mediated Instruction and the control group (38) taught using the Conventional Method. Researcher-made reading test, self-perception in reading and self-perception in writing inventory validated by language experts, and writing prompt for informative essay were administered to both groups of students before and after the treatment period which ran for 13 weeks. Partial least squares structural equation modeling was used to examine the correlations among variables and ANCOVA was used to determine the effect of web-mediated and conventional writing instruction on students' writing performance. Results of independent t-test show that there is a significant difference in the pre-test and posttest writing scores of both experimental and control groups. However, there is no significant difference between the reading and writing performance of experimental group and control group at p < 0.05) based on ANCOVA results. Therefore, web-mediated writing instruction via weblogs and conventional writing instruction are equally effective in enhancing students' writing performance. As regards, correlations of variables tested in this study, for experimental group, reading performance positively significantly affects writing performance. Both self-perception in reading and self-perception in writing insignificantly affect writing performance. Reading performance is insignificantly correlated with self-perception in reading. For control group, self-perception in reading and reading performance positively significantly affect the control group's writing performance. Reading performance is insignificantly correlated with self-perception in reading and self-perception in writing. In both groups, self-perception in reading is positively correlated with self-perception in writing. Hence, educators should develop students' positive attitude towards reading to effect positive attitude towards their writing. As what research shows, positive self-concept in writing will more likely result in improvement of writing skills.